Guerrero (elbow) began a rehab assignment with High-A Greenville on Tuesday and worked around three walks and one hit in a scoreless inning in his first appearance.

The one-inning outing marked Guerrero's first appearance at any level since June 27, as he's been on the shelf for two months while recovering from a right elbow strain. Guerrero is expected to eventually shift his rehab assignment to Triple-A Worcester, and once he gets a few more minor-league appearances under his belt, he could re-emerge as an option for Boston's bullpen.

The Red Sox optioned Moran to Triple-A Worcester on Thursday, Tim Healey of The Boston Globe reports.

Moran will head back to Worcester as the Red Sox open up a spot in the bullpen for Justin Slaten (shoulder), who was reinstated from the injured list. After being recalled from Triple-A on Tuesday, Moran didn't make any relief appearances during his two-day stint with the big club.

The Red Sox activated Slaten (shoulder) from the 60-day injured list Thursday, Tim Healey of The Boston Globe reports.

Slaten is finally ready to rejoin the Boston bullpen after missing the past three months with right shoulder inflammation. The 27-year-old should eventually return to a setup role for the Red Sox, but he'll likely be eased into such situations following a long layoff.

Montero tossed 2.2 scoreless innings of relief in Wednesday's 7-0 loss to the Athletics. He walked one batter and struck out four.

After starter Casey Mize was tagged for five runs in just 3.1 innings, Montero came on and gave the Tigers some valuable long relief. It was the veteran righty's longest outing of the season, and he's now covered two or more innings four times this year. Montero has been fairly effective in Detroit since coming over before the trade deadline, posting a 3.48 ERA and 1.06 WHIP across 10.1 innings with his new team.

Slaten (shoulder) is expected to be activated from the 60-day injured list ahead of Thursday's series finale in Baltimore, Christopher Smith of MassLive.com reports.

Slaten hasn't pitched in the majors since late May, when he was placed on the injured list with what was initially described as right shoulder inflammation. He later learned that his transverse process was pressing against nerves, causing soreness. Slaten looks to be healthy again after tossing three scoreless innings across three rehab appearances at Triple-A Worcester, and he could eventually move back into a setup role for Boston. Slaten posted a 3.47 ERA with four holds, three saves and a .171 batting average against in 24 appearances for Boston prior to landing on the shelf.

Thompson (shoulder) is scheduled to throw Friday after pitching a scoreless inning for Triple-A Reno on Tuesday, MLB.com reports.

The outing Tuesday was the first game appearance of a rehab assignment for Thompson. Following a live batting practice and a sim game, Tuesday's appearance was expected to be his final step before activation; however, the report indicates Friday's throwing session is the only confirmed next step in the process. The Diamondbacks may be waiting for September when rosters can be expanded be to 28 players (14 pitchers).

Mlodzinski didn't factor into the decision Wednesday against the Cardinals, allowing one run on three hits and three walks with four strikeouts across three innings.

Mlodzinski drew his 11th start of the season, though he threw just 46 pitches before handing the ball off to Bubba Chandler. Mlodzinski has been excellent in August, owning a 2.04 ERA and a 22:6 K:BB across 17.2 innings spanning seven appearances. Unless the Pirates look to give a starter an additional day of rest or move to a six-man rotation, Mlodzinski should move back to his typical relief role.

Chandler (1-0) picked up the win Wednesday against the Cardinals, allowing one hit and one walk with three strikeouts over four scoreless innings.

Chandler served as a long reliever for a second straight appearance, taking the mound to start the fourth inning and firing four scoreless frames. Chandler has now logged a save and a victory in his first two MLB appearances, and he's allowed no runs on three hits with six strikeouts across eight innings during that stretch. The highly touted prospect has looked as advertised through two appearances.

Santana picked up the save Wednesday against St. Louis, allowing one walk and no hits with one strikeout during a scoreless ninth inning.

Santana shut the door on the Cardinals to close out the Pirates' 2-1 win, walking Thomas Saggese with two outs before getting Pedro Pages to ground out. It was a bounce-back effort for Santana, who surrendered a run and took the loss Monday in St. Louis. That run is the only one he's allowed in his past eight innings of work. Santana has converted on 10 of his 12 save chances this season and has a 2.37 ERA and 0.91 WHIP.

Latz didn't factor into the decision Wednesday against Los Angeles, allowing two runs on four hits and one walk with five strikeouts across 4.1 innings.

The Rangers selected Latz to fill Nathan Eovaldi's (shoulder) spot in the rotation, and Latz fared well in the position. He threw just 66 pitches, up from the 43 pitches he threw in his previous appearance, and managed to pitch into the fifth frame. In four starts this season, Latz has a 3.38 ERA and a 19:8 K:BB across 18.2 innings. He's tentatively scheduled to make his next start against the Diamondbacks early next week and could continue building up his workload.