The Cardinals are hopeful O'Brien (shoulder) will be available to pitch Friday against the Giants, the St. Louis Post-Dispatch reports.

O'Brien hasn't pitched in a week due to lingering right shoulder soreness, but he played catch earlier this week and could be cleared for game action after the team's off day Thursday. The 30-year-old collected two saves and three holds in August and boasts a 1.69 ERA and 35:17 K:BB over 37.1 innings this season.

Blewett (elbow) allowed two runs on three hits over an inning in his first rehab appearance with Triple-A Norfolk on Wednesday.

It was Blewett's first appearance in a game since he went down with right elbow discomfort just before the All-Star break. He'll need a few more rehab outings but could be activated from the 60-day injured list when first eligible Sept. 15.

Vesia (oblique) struck out one in a perfect inning in his first rehab appearance with Triple-A Oklahoma City on Wednesday.

Vesia has missed the last two weeks of action with a right oblique strain but didn't seem to show any rust in his first rehab outing. The reliever could make one more rehab appearance before being activated from the 15-day injured list on Sunday, the first day he's eligible.

Walker earned a save against the Rockies on Wednesday, allowing one hit while striking out one batter over a scoreless two-thirds of an inning.

It didn't seem like Walker would be needed with the Giants beginning the bottom of the ninth inning with a 10-5 lead, but he was called upon to put out a fire after Colorado loaded the bases with one out. Walker gave up a sacrifice fly followed by a two-run double, but none of those runs were charged to his ledger. Since he entered with the tying run on deck, Walker was able to get credit for a save by finishing out the contest despite allowing his team's lead to shrink. He's now completed 10 straight scoreless appearances, posting a 0.86 WHIP and 12:0 K:BB over 9.1 frames during that span.

Romero earned a save against the Athletics on Wednesday, allowing two hits while striking out one batter over 1.2 scoreless innings.

Romero entered with one out in the top of the eighth frame when St. Louis led by two runs. He allowed a single to the first batter he faced before retiring the next two hitters. Romero then returned for the ninth and gave up a leadoff single, but that was quickly wiped out on a double play. Romero subsequently wrapped things up to finish with his seventh save of the season, four of which have been longer than an inning in length. With Riley O'Brien (shoulder) currently on the shelf, Romero is the clear top option for save chances for the Cardinals.

Detmers earned the save in Wednesday's 4-3 win over the Royals, striking out two in a perfect ninth inning.

With Kenley Jansen pitching three out of the last four days, Detmers was called upon to protect a one-run lead and shut down the Royals on 13 pitches. The right-hander hasn't allowed a run in 12 of his last 13 appearances and has given manager Ron Washington reason to utilize him in high-leverage scenarios like Wednesday's when necessary.

Dana didn't factor into the decision against the Royals on Wednesday, allowing two runs (one earned) on two hits and one walk while striking out four over five innings.

Making his first start of the season and the fourth of his career, Dana was sharp outside of the third inning, when a single, a walk and an error combined to bring home two runs for Kansas City. Otherwise, the 21-year-old faced the minimum in each of his other four frames, showing good poise and efficiency (70 pitches) in his first big-league outing since May. With Wednesday's performance, Dana should be in line for at least another turn as the Angels look to evaluate him down the stretch.

Cantillo (4-3) earned the win over the Red Sox on Wednesday, allowing one run on five hits and two walks while striking out seven over six innings.

Cantillo was impressive against a tough Boston lineup, completing six innings for the first time this season. The southpaw's lone blemish came in the fourth inning when Boston scratched across a run on three singles, but he quickly rebounded to retire seven of the final eight batters he faced. Wednesday's performance continued a strong stretch in which Cantillo has now allowed exactly one run in three straight outings. Across his nine starts this year, the 25-year-old has posted a 3.68 ERA and 51:24 K:BB over 44 innings.

Woodford walked one and struck out one in a scoreless ninth inning Wednesday to record his third save of the season in a 2-0 win over the Rangers.

Arizona manager Torey Lovullo continues to mix and match at the back of his bullpen, as Andrew Saalfrank worked the eighth inning against the heart of the Texas order before Woodford handled the ninth. The 28-year-old right-hander still has two of the Diamondbacks' last three saves, with Taylor Rashi getting the other and all three of Woodford's saves have come since Aug. 23. His ratios don't make a compelling case for consistent high-leverage usage however, and over 20 innings since the beginning of August, Woodford's posted a 4.95 ERA, 1.35 WHIP and 11:6 K:BB.

Koenig secured the save in a 6-3 win over the Phillies on Wednesday, throwing a clean ninth inning with one strikeout.

Koenig got the call to earn his first save of the season Wednesday. With the possibility of having to face superstar lefties Kyle Schwarber and Bryce Harper in the frame, the southpaw likely received the nod over righty Abner Uribe for matchup-related reasons. Closer Trevor Megill (elbow) is targeting a return by mid-September, so Koenig will likely revert back to a setup role before long. Koenig has a decent 3.32 ERA and 1.26 WHIP over 57 innings while recording 25 holds this year.