Every time the Rays’ pitching staff is about to get healthy, it seems, another injury pops up. That was the case on Wednesday, when Tampa Bay reinstated right-hander Pete Fairbanks from the 10-day injured list but placed fellow high-leverage reliever Diego Castillo on the 10-day IL.

Right groin tightness forced Castillo to the IL, the Rays announced, with his assignment made retroactive to Tuesday. Manager Kevin Cash said he was “cautiously optimistic” that Castillo will only be sidelined for 10 days or something “very close” to the minimum IL stint. Castillo felt the tightness when he pitched Monday in the Rays’ 7-3 win over the Angels, according to Cash.

Castillo earned seven of Tampa Bay’s first 10 saves this season, tied for second most in the American League behind Texas’ Ian Kennedy. The right-hander had taken on the top high-leverage assignments in the Rays' bullpen, as the club began the season without right-hander Nick Anderson and lost Fairbanks due to a strained right rotator cuff on April 9.

In 14 outings, Castillo has put together a 3.14 ERA and 1.12 WHIP, with 20 strikeouts and six walks in 14 1/3 innings. Fairbanks only made three appearances before his shoulder sidelined him for nearly a month, but he said Tuesday that he has felt good facing hitters in simulated games. Fairbanks, who posted a 2.70 ERA with 39 strikeouts in 26 2/3 innings last season, will likely take on the bulk of the high-leverage, late-inning work in Castillo’s absence.

“We know we've had some key guys nicked up in the bullpen,” Cash said. “What Diego's done to this point -- he's always been there the last three, four years, just been outstanding, and I know he's going to be down. We think it's going to be a short period of time. But anytime you can add a guy like Pete Fairbanks that has been there, done that and really established himself as just a high-end reliever against righties and lefties, it helps a lot.”

This is the second straight day the Rays have swapped pitchers on and off the 10-day injured list, as they activated right-hander Collin McHugh (low back strain) on Tuesday while putting starter Michael Wacha (right hamstring tightness) on the shelf.

The Rays’ various pitching injuries have created opportunities for other pitchers to step up. Josh Fleming, Shane McClanahan and Luis Patiño have moved into starting/bulk-inning roles after beginning the season at the alternate training site. Cash has mixed and matched right-hander Ryan Thompson and left-hander Jeffrey Springs in key late-inning spots. And right-hander Andrew Kittredge, the Rays’ opener against the Angels on Wednesday night, has pitched important innings in a variety of roles.

The Rays dealt with plenty of pitching injuries last year, too, and Cash credited the organizational depth assembled by general manager Erik Neander for helping them get through another rash of injuries during the first month of this season.

“It’s part of the game. It's unfortunate. You don't like to see anybody go down. You certainly don't like to see your key guys that contributed so much go down,” Cash said. “Players don't come into the season anticipating or expecting to get hurt, and that's the right mindset. But I think from an organizational philosophy, you have to anticipate that there are going to be some times throughout the season where it's going to get really challenging and sketchy, and how are we going to fulfill different roles? And I think Erik and his group do a tremendous job.”

Around the horn
• First baseman Ji-Man Choi, returning from arthroscopic surgery on his right knee, began a Minor League rehab assignment with Triple-A Durham on Tuesday night. Choi played five innings at first base and went 0-for-2 with a sacrifice fly. He went 1-for-4 with a double, a walk and two strikeouts as Durham’s designated hitter on Wednesday night.

• The Rays saw more encouraging performances from their loaded Triple-A Durham affiliate in a 4-0 win over Memphis on Wednesday. Right-hander Joe Ryan struck out nine in five scoreless innings. Vidal Bruján, starting in center field, led off the game with a home run. And Wander Franco, playing second base with slick-fielding Taylor Walls at shortstop, drove in Bruján (who singled and stole second) on a double to right field in the third inning then hit his first Triple-A homer in the fifth.

• Right-hander Shane Baz, the Rays’ No. 6 prospect, dominated in his season debut for Double-A Montgomery. Baz worked four hitless innings while striking out four and walking just one batter on Wednesday night.

• Right-hander Cole Wilcox, one of the prospects acquired from the Padres in the Blake Snell trade, made an impressive professional debut on Wednesday afternoon for Low-A Charleston. The 21-year-old Wilcox, the Rays’ No. 9 prospect according to MLB Pipeline, allowed only two hits while striking out five over four scoreless innings. Outfielder Nick Schnell, Tampa Bay’s 30th-ranked prospect, homered in the RiverDogs’ 8-2 win over Myrtle Beach.