Megill's (elbow) bullpen session went well Thursday, and he is expected to be activated from the injured list by Sept. 16, Adam McCalvy of MLB.com reports.

This marked Megill's first time throwing off of a mound since he hit the injured list Aug. 27. There weren't many other details provided, as the assembled media members were called into manager Pat Murphy's office while Megill was throwing. Regardless, Megill should be back for the final couple weeks of the season, barring a setback.

Atlanta recalled Hernandez from Triple-A Gwinnett on Thursday.

Hernandez will give manager Brian Snitker a fresh bullpen arm. The hard-throwing righty has a 2.72 ERA but also a 33:30 K:BB over 36.1 frames this season with the big club.

The Mets claimed Suero off waivers from Atlanta on Thursday.

Suero has given up eight runs in only 6.1 innings in the majors this season, but the Mets will take a chance on him based on his 1.35 ERA and 1.04 WHIP through 46.2 frames in Triple-A.

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.

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.

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.

Pomeranz allowed two runs on three hits while only retiring two batters in relief during Wednesday's 5-1 loss to the Atlanta.

Pomeranz came on in the top of the seventh inning with two runners on and Chicago up 1-0, and the lefty promptly served up a three-run home run. That saddled Ben Brown with the loss in relief, though it was certainly a discouraging outing for Pomeranz, who has allowed two runs on three hits in two of his last three appearances. Despite the hiccup, the veteran still has a tidy 2.45 ERA on the season, and his track record this year suggests he'll be able to get back on track.