Slaten (shoulder) has yet to play catch since being placed on the injured list Sunday, Christopher Smith of MassLive.com reports.

Slaten was diagnosed with shoulder fatigue when he was placed on the injured list, so the issue didn't appear to be overly serious. However, he's likely to be sidelined until at least late June given his lack of progress.

Stephenson had two MRIs that showed no structural damage to his right biceps, and he's been diagnosed with a stretched nerve, Rhett Bollinger of MLB.com reports.

While imaging provided some positive news for the veteran reliever, the stretched nerve diagnosis comes with an uncertain timeline for a return. Stephenson called the issue a "freak injury" and stated that he's unsure how long he'll be out of action. He added that the only treatment for the injury is rest, and at this point it's unclear if Stephenson will be ready to return from the IL when eligible June 15.

The Red Sox recalled Winckowski (elbow) from Triple-A Worcester and transferred him to the 60-day injured list Saturday.

Winckowski has spent most of the season with Triple-A Worcester, and he landed on the minor-league injured list due to elbow inflammation in mid-May. He'll now be sidelined until at least after the All-Star break.

Criswell was optioned to Triple-A Worcester on Saturday.

Criswell has bounced back and forth between Boston and Worcester this season and made two appearances during his most recent stint in the majors. He threw three innings Friday against the Yankees, so the Red Sox will option him and get a fresh arm for their bullpen.

The Mariners reinstated Thornton (abdomen) from the 15-day injured list Saturday.

Thornton landed on the 15-day injured list May 9 due to appendicitis, and it took three weeks for him to recover enough to embark on a rehab assignment with Triple-A Tacoma. He'll claim the spot in the Mariners' bullpen that was vacated by Casey Lawrence, who was designated for assignment in a corresponding move. Thornton posted a 5.87 ERA, 1.30 WHIP, five holds and an 11:4 K:BB across 15.1 innings prior to his stint on the IL.

The Mariners designated Lawrence for assignment Saturday.

It's the sixth time Lawrence has been DFA'd this season -- the fifth time by the Mariners. He has appeared in five games for Seattle this season and has a 3.00 ERA and 1.40 WHIP across 15 innings. The move makes room on the roster for Trent Thornton (abdomen), was reinstated from the 15-day injured list.

The Royals optioned Bowlan to Triple-A Omaha on Saturday.

Bowlan is coming off a rough outing against the White Sox on Friday, when he allowed five runs (three earned) on two hits and four walks while striking out one batter in 1.1 innings. In a corresponding move, Kansas City selected Trevor Richards' contract from Omaha.

The Royals selected Richards' contract from Triple-A Omaha on Saturday.

Richards signed a minor-league contract with the Royals on May 9 after being released by the Cubs three days prior. The 32-year-old right-hander struggled with Triple-A Iowa, but he's been better out of the bullpen for Omaha, where he has a 1.69 ERA, 1.86 WHIP, two saves and an 11:5 K:BB across 10.2 innings. Richards will take the spot on the Royals' 26-man roster vacated by Jonathan Bowlan, who was optioned to Triple-A in a corresponding move.

Erceg (back) threw live batting practice Friday and is set to begin a rehab assignment with Triple-A Omaha on Sunday, MLB.com reports.

Erceg was placed on the injured list May 30, retroactive to May 27, making him eligible to return June 12 against the Yankees. Prior to hitting the shelf, the 30-year-old was in the midst of a strong season, recording a 1.96 ERA and 0.74 WHIP with 13 holds over 23 innings. Barring any setbacks during his rehab assignment, the right-hander should return to his setup role with the Royals in the near future.

Coulombe (forearm) tossed one scoreless inning in his first rehab outing with Triple-A St. Paul on Friday.

Coulombe landed on the 15-day injured list May 18 due to an extensor strain in his left forearm. He was cleared to embark on a rehab assignment Friday, but the veteran southpaw may not need more work in Triple-A and could rejoin the Twins' bullpen in the coming days, per Aaron Gleeman of The Athletic. Coulombe hasn't given up a run across 16.2 major-league innings this season while posting a 0.60 WHIP, two saves and a 19:2 K:BB.