The Red Sox got some more reinforcements Tuesday night, with right-hander Chris Martin returning from the 15-day injured list after taking time off to deal with anxiety. Now the club could be days away from getting another key player back as well.

Outfielder Wilyer Abreu began what is expected to be a brief rehab assignment with the Worcester Red Sox on Tuesday, going 0 for 4 with a walk in his first game back. Abreu will likely play two games with the WooSox, and if all goes well he could join the big league club in Cincinnati this weekend when they open their upcoming series against the Reds.

Shortstop David Hamilton, who has been battling side soreness and was removed from Monday’s game, is also feeling much better and should return to the lineup soon, manager Alex Cora told reporters in Toronto on Tuesday.

The club did get bad news on the prospect front, however, as right-hander Luis Perales recently underwent an MRI that confirmed the top Red Sox pitching prospect has damage in his UCL. He is expected to miss the remainder of the season and will undergo elbow surgery in the near future, either an internal brace procedure or a full Tommy John surgery.

In order to accommodate Martin’s return to the bullpen, the Red Sox made the surprising decision to option No. 5 starter Cooper Criswell to Triple-A. Criswell has been effective in the back of the rotation, posting a 4.15 ERA over 12 games (11 starts), but Cora told reporters the move came down to roster flexibility.

Criswell still has minor league options remaining, and with a light stretch including three off-days in 12 days starting Thursday, the Red Sox can get by with a four-man rotation for essentially the entire 15-day stretch Criswell must remain in the minors (or less if someone gets injured in the meantime). The only day in the next two weeks Boston will need a fifth starter is Sunday in Cincinnati, but the Red Sox have Chase Anderson and Brad Keller on the roster, both bulk relievers with starting experience, and Josh Winckowski is stretched out in Triple-A and could be called up to make a spot start in a pinch.