Fantasy Baseball: Buy into recent call up pitchers like Jon Duplantier, Corbin Martin?

We've reached the point of the season when attrition starts to impose its will upon Fantasy players. Injuries happen. Roster spots open up. Deadlines pass. Call ups begin. With little warning, we're welcomed by a swarm of new faces on major league rosters.

Chief among these are "pop up" starting pitchers, which makes sense considering injury rates among pitchers are higher than hitters. They're not always top prospects, but these new arms are often prospect-leaning and can be difference makers, so we need to pay attention.

However, with so little information outside of scouting reports and minor league stats, how do we process them all? Using stats from one major league start to make a projection going forward won't cut it — we shouldn't ignore it, but there's a lot of noise in one start to overweight it.

Instead, let's assess these new faces through the lens of something that does become meaningful more quickly — their raw stuff. The objective is to give us a better sense of what to expect from them moving forward and help you answer questions like, "Which one should I pick up?"

Borrowing from research that went into our raw stuff pitching metric, ACES, here are eight "pop up" arms with their stuff put under a microscope, sorted here by rough priority order:

(NOTE: As a refresh, percentiles for "raw stuff" are determined as follows:

• Velocity: Higher velocity is better
• V Mov: More "rise" is better for fourseam, more drop is better for other pitches
• H Mov: More absolute movement is better

All pitch data is courtesy of Baseball Prospectus' PITCHf/x leaderboard, as of 5/31/19.)

CORBIN MARTIN, HOU

You pay attention anytime a new Astro pitcher finds himself in the rotation. Heck, Wade Miley has added 4.5% to his strikeout rate and currently sports a 3.25 ERA and 1.14 WHIP! If nothing else, the Astros know how to identify and develop pitching. It should come as no surprise, then, that the Astros are at it again:

Rated as the Astros third best prospect and 50th overall going into the season, Martin has the most pedigree on this list and his 49% ownership on CBS (highest on this list) reflects that.

Look at his fourseam here, the perfect "rising" heat to use high in the zone:

Or the changeup, with its elite combination of velocity and movement:

The curve has been his best pitch by called strikes plus whiffs (CSW%) to date, ranking 81st percentile among curveballs:

And the slider earned the highest future grade (60) from FanGraphs:

However, while Martin has plus velocity across the board, he hasn't yet been able to produce whiffs at the rate you might expect in his brief 16 major league innings:

FanGraphs prospect reports suggest this isn't a new thing, stating before the 2019 season:

"He still doesn't post the strikeout rates that you'd assume from a possible No. 2 or 3 starter in the Astros farm system. Sources with knowledge in this area indicate that Martin should see more K's in 2019 if he can make a couple subtle adjustments to how he uses his pitches and fully unlock his potential."

When you look at his movement numbers and then look at his spin numbers — referring to spin efficiency — might there be potential to generate additional movement and get more from his spin ability?

His spin percentiles: 

Currently sporting a 5.51/7.62 ERA/FIP, there's the risk that Martin will be sent back down — at least for now. With a 40/50 current/future grade from FanGraphs, command could be an issue for Martin to continue to refine, holding him back from greater success in the majors. 

But with top shelf velocity and spin across the board, combined with his pedigree and organization, I'd rather hold onto the stuff and let the Astros force my hand.

Verdict: 12-team pickup

JON DUPLANTIER, ARI

Let's pour one out for Luke Weaver, who ACES loved to rebound and was one of 16 pitchers we profiled as an ideal candidate for this current juiced ball environment. We're still awaiting further news, but you never want to hear "forearm tightness" and "pitcher" in the same sentence. Let's hope for the best.

Alas, "next man up," as the saying goes. And, for now, that man is Duplantier, a top-100 prospect who ranked 87th on FanGraphs' list for 2019. As a top prospect, naturally expectations are higher. In that regard, his most recent prospect report from FanGraphs doesn't disappoint:

"The lost innings resulted in an Arizona Fall League stint, during which Duplantier was arguably the best non-Whitley pitching prospect who was a lock to start. Despite the biceps issue, his velocity was fine in the fall. Duplantier sits 93-96 and makes heavy use of three good secondary pitches."

The only major league data we have on Duplantier is from his 12 innings in relief — potentially skewing the results as relievers are able to pitch in shorter stints with greater velocity and a tighter pitch mix — but even as a reliever, his wide arsenal was on full display:

It's a tiny 187-pitch sample, but he threw five (!) pitches more than 10% of the time! Five! Four of the five pitches possess above-average velocity with exception of the changeup, although it does possess an above-average 8.9 mph velocity differential from his fastball (league average is closer to 7.8 mph). All his pitches rate as average-to-above average by movement, with his fourseam (rise), curve (drop), slider (run) and changeup (drop) all rating in the top 40% or better.

In the small sample, his fourseam and curve have been doing the heavy lifting for whiffs, both ranking in the top 20% by whiff rate.

Here's the fourseam striking out Kyle Schwarber:

And the changeup with its above-average velocity gap and top 20% drop:

Early returns on his command aren't great as Command+ has him in the bottom quarter of the league. With a 50/55 grade on current/future command, however, there's promise for improvement. We don't know how long the Diamondbacks plan to keep him in the rotation, but injuries might force their hand and Duplantier's wide arsenal of good stuff makes him an intriguing add. Add in his cool-glasses look and French pronunciation — "doo-PLON-tee-ay," per Baseball Reference — and it's a no-brainer.

Verdict: 12-team pick up

TYLER BEEDE, SF

Just like Martin and Astros pitchers, any time a new Giants pitcher emerges — that is, someone who pitches half their games in extreme pitcher haven Oracle Park — we must pay attention. A first round pick of the Giants in 2014, Beede isn't exactly new to us. He debuted in the majors last season, but after two borderline disastrous starts where he issued more walks than innings pitched, his time with us was over.

With fastball velocity back up and averaging nearly 95 mph, his stuff looks quite good though!

The drop on his pitches — 33rd percentile "rise" on the fourseam would indicate larger drop than average — has helped drive Beede's 99th percentile rate on generating grounders-plus-popups. Meanwhile, the plus velocity on his fastball and elite fourseam-changeup velocity gap (over 10 mph) have driven nice whiffs (top 20%) for both pitches (fourseam and change).

Here he goes upstairs with the fourseam to strikeout Freddy Galvis with 96 mph gas:

And now you see the changeup at 84 mph, 12 mph slower than the fourseam he used above!

With three above-average pitches by stuff — top 20% velocity on the fourseam, good velocity and drop on the curve, elite fourseam-changeup velocity gap (over 10 mph) and top 15% drop on the changeup — the big question becomes, "what about command?"

On that, we have conflicting answers. A quick look at his walk rates and his 40-grade command from FanGraphs seems to shut the door quickly on that question. However, he does grade as above average by Command+ this season. Which one is it?

I'm inclined to believe it's the former and that command will continue to be Beede's kryptonite. It is, however, hard not to be intrigued by a pitcher with stuff in Oracle Park — particularly one with a good shot to remain in the rotation:

Verdict: Borderline 12-team pick up

DEVIN SMELTZER, MIN

Another pitcher with cool glasses, Smeltzer's early-season performance in Double-A — 0.60 ERA, 0.73 WHIP and 30.6% strikeout rate in 30 innings — caused quite a surprising stir, most notably by Alex Chamberlain, of CBS and RotoGraphs, in his Cistulli Fringe Five-like series, Peripheral Prospects.

Lo and behold, Smeltzer was called up to fill in for Michael Pineda, who was placed on the IL for knee tendinitis. Smeltzer's debut was … not bad! Against a top-10 offense in Milwaukee: 

6 IP, 3 H, 0 ER, 0 BB, 7 K, 15.9% Whiff%, 36.2% CSW%.

Of course, it was only one start, but the whiff and CSW figures would be good for the top 5% in the league!

By raw stuff, he doesn't grade out quite as strong:

Pitching from the left side, Smeltzer sits a hair under 90 (89.9 mph), ranking 215th out of 231 starting pitchers who have thrown a fourseam fastball this season. He makes up for the poor velocity with good movement on all his pitches, punctuated with elite drop on the changeup. Eric Longenhagen and Kiley McDaniels touched on that in their preseason Twins prospect report, where Smeltzer ranked as the Twins 22nd-best prospect:

"Repertoire depth, plus fastball and breaking ball spin, and efficient strike-throwing all mix with the mechanical deception to enable Smeltzer's success despite a lack of velocity."

About that "mechanical deception," Longenhagen and McDaniel noted Smeltzer has "one of baseball's funkiest deliveries." Let's take a peek at that delivery and the fourseam:

Here he's getting Christian Yelich to chase two back-to-back pitches for a three-pitch strikeout — first with the curve on 0-1 (swinging strike) then putting him away with the changeup (after he earned a called strike with his changeup on the first pitch of the at-bat):

Two things we've alluded to but haven't explicitly mentioned: per prospect reports, Smeltzer also has a slider in his arsenal, a potential fourth pitch to give hitters varied looks and, like Duplantier, has decent command with a 50/55 current/future grade given by FanGraphs.

It's an odd package, but an intriguing one nevertheless. With his spin ticking up "pretty significantly" the last couple years, per FanGraphs, perhaps that's why we're now seeing Smeltzer in the show. The Twins don't have the most infallible rotation but with Pineda pitching better in May (19.2% K-BB%) before the knee injury and the never-ending shadow of Dallas Keuchel — not to mention Smeltzer's minus-minus velocity — his hold on a spot in the rotation is shaky, at best.

Nevertheless, seeing top 5% whiffs and CSW — small sample be damned — is enough for me to want to see if there could be more.

Verdict: 12-team streamer, 15-team pick up

CAL QUANTRILL, SD

While the ERA hasn't been great (5.14), Quantrill has flashed nice stuff in his four starts and 21 major league innings for the Padres this season — look no further than his 13.7% whiff rate (83rd percentile). He's got quite the wide arsenal:

Although wide, it's a bit of a mixed bag. He's only thrown 12 of them but the curve doesn't appear above average in any way — by velocity, drop, horizontal movement, command, whiffs, called strikes, you name it. Unless he can tweak his way into something better, perhaps he should consider dropping it and focusing more on the slider, a pitch that looks good by velocity and drop and has been top 20% by whiffs and CSW so far.

His fastball is in the top 20% by both velocity and "rise" and his changeup plays really nicely off it, with an elite 10.1 mph gap that's helped generate a top 15% whiff rate and CSW for the pitch — below-average velocity and drop be damned. So, we've got a good fastball/changeup combo and a good breaker in the slider.

What about command? Another mixed bag here as FanGraphs rated his command with a 40/50 current/future while Command+ has seen him closer to average — with above-average command on the fourseam, sinker and slider. Despite what's likely average command at best, if we had a clearer idea of the Padres plan for him, he'd see himself higher on this list.

Verdict: Deep league stash

ZACH PLESAC, CLE

A preseason prospect of note in the Indians system, Plesac's fastball velocity jumped from 90-94 mph in college and immediately following Tommy John Surgery to 94-97 mph this season. The velocity boost helped the 24-year-old earn video-game numbers — 0.96 ERA in Double-A (37 IP) and 2.25 ERA in Triple-A (20 IP) — and a fast promotion in the minors this season.

Known as a "changeup artist," Plesac stayed true to form and largely leaned on his fourseam and changeup in his debut. However, aside from the fourseam — buoyed by its newfound velocity increase — Plesac's stuff didn't flash as well as you'd like:

While the changeup didn't impress in his debut — only generating an 8% whiff rate — and has below-average drop, it does have above-average velocity and an above-average velocity gap (8.4 mph) from the fastball. Not quite the "changeup artist" I was hoping to see and, without a firm rotation spot, I'd be fine letting Plesac sit on the waiver wire in all but the deepest of leagues.

Verdict: Deep league streamer

GENESIS CABRERA, STL

Cabrera was called up to fill Michael Wacha's spot in the rotation, following the veteran's demotion to the bullpen. Acquired as part of the Tommy Pham trade last season, Cabrera wasn't exactly lighting it up in Triple-A before he got the call, posting a 6.35 ERA, 1.56 WHIP and 21% strikeout rate.

He does have some stuff though:

Considering he throws from the left side, he's got an electric fastball that nearly averaged 97 mph in his debut. It also possesses above-average "rise" and generated an 87th percentile CSW% in his debut.

The velocity is the carrying tool — particularly as a lefty — as he has above-average velocity across his entire arsenal. The secondaries he flashed in his debut, however, are both well below average by movement. While his changeup has particularly poor "drop" relative to peers, it earned 91st percentile whiffs in his debut, likely driven by a 9.4 mph fastball-changeup velocity gap that sits well above average.

Prospect reports indicate Cabrera also has a slider/cutter-type pitch but he didn't appear to use it in his debut. Overall, the velocity is nice but with minus command and lack of a third pitch — not to mention the looming presence of a rehabbing Alex Reyes and Wacha working through his issues in the bullpen — it's hard to imagine Cabrera staying in the rotation for too long, something FanGraphs prospect team predicted, as well.

Verdict: Deep league streamer

LUCAS SIMS, CIN

Sims is a former prospect of note and first round pick of the Braves acquired by the Reds in the Adam Duvall trade last season. Following his major league debut with the Reds on May 28th, he was promptly sent back down to Triple-A as of May 30th, but not before his fourseam flashed 98th percentile spin and his stuff generated a 19% whiff rate (99th percentile) and 36% CSW% (97th percentile):

He may call the formidable Great American Ballpark home, but keep a close eye on him should he be called back up — the Reds rotation has been among the best five by ERA but isn't completely bulletproof.

Verdict: Watch list

Hopefully this brings you up to speed and gives you a perspective on the "new" guys we've seen recently. Now is not the time to rest, however, as more are here or coming — Mitch Keller of the Pirates (37th on FanGraphs top 100 prospects — oddly, I can't find any public pitch tracking data on him!) and Jose Suarez of the Angels (79th on FanGraphs top 100 prospects), to name a couple.

While it would be great if we did, we simply don't have the luxury of waiting for sufficient sample sizes when these new pitchers pop up. We need to make our best educated guesses based on the most reliable information we do have — often times, that's their raw stuff.