ANAHEIM -- Twins right-hander Trevor May took a big step in his recovery from last year's Tommy John surgery, beginning his Minor League rehab assignment by throwing three scoreless innings with Class A Advanced Fort Myers on Saturday.
May, who underwent the surgery in March 2017, had previously been pitching in extended spring training but officially began his 30-day rehab assignment on Saturday. He allowed one hit, walked three and struck out five while throwing 58 pitches against Dunedin.
May is expected to continue to rehab with Fort Myers before moving up to Triple-A Rochester later this month. The Twins will stretch him out as a starter to keep their options open, although there remains a chance he could rejoin Minnesota as a reliever. He's eligible to be reinstated from the 60-day disabled list on May 28 and is expected to be ready to return by early June.
May, 28, has a career 5.14 ERA with 214 strikeouts and 65 walks in 203 innings. He hasn't started since the 2015 season, but the Twins were stretching him out to start again last spring before he sustained a torn ulnar collateral ligament while pitching an exhibition game against Team USA prior to the 2017 World Baseball Classic.
Injury updates
• Catcher Jason Castro, who is on the 10-day DL with a torn meniscus in his right knee, will head to Colorado for a second opinion on his right knee from Dr. Robert LaParade. Castro is eligible to return from the DL on Tuesday, and the Twins were originally hopeful he could return by then, but Castro hasn't progressed as well as the Twins had hoped. Castro received a cortisone shot in his right knee, but the issue hasn't gone away.
Castro has had several injuries to his right knee in the past, including missing the 2011 season with a torn ACL and undergoing arthroscopic surgery after the '13 season.

• Right-hander Ervin Santana, recovering from surgery to remove calcium deposits from his right middle finger, threw a 50-pitch bullpen session while incorporating sliders for the first time on Saturday.
He'll progress to throwing to hitters on Monday and Thursday in Fort Myers before moving on to a start in extended spring training on May 21 and in a rehab start on May 26. Santana isn't eligible to return until May 28, and if all continues to go well, he is expected back in early June.
• Third baseman Miguel Sano continued to test out his strained left hamstring by hitting, running and fielding at Angel Stadium on Saturday, but Twins manager Paul Molitor said it wasn't at the same intensity as the previous two days. Sano continues to have soreness in his hamstring and Molitor said a return or a rehab assignment isn't imminent.