MESA, Ariz. -- Rehabbing right-hander Henderson Alvarez took a big step Monday, throwing off a mound for the first time since undergoing shoulder surgery in July.
Alvarez, who hopes to join the A's rotation as soon as May, threw 20 pitches in the bullpen session and reported no issues.
"He's one of those guys we're going to have to hold back. He's real enthusiastic," A's manager Bob Melvin said. "Got a little bit tired at the end, and that's what we want to push him to do. He threw quite a bit before he threw off a mound."

Alvarez will continue throwing bullpen sessions every couple of days and, barring any setbacks, could be facing hitters in Minor League games come April.
The 2014 All-Star pitcher, still just 25, has the potential to help create a formidable 1-2 punch with ace Sonny Gray when healthy.
Worth noting
A's infield prospect Rangel Ravelo drove in the only two runs of Monday's intrasquad game at Fitch Park with a single off lefty Dillon Overton. … Another highly regarded infield prospect, Matt Chapman, made a fantastic diving play at third base in the game, warranting praise from Melvin. … Catcher Josh Phegley, one of several players in camp slowed by a flu bug, returned to workouts Monday but did not participate in the intrasquad game. … Rich Hill, Chris Bassitt and Raul Alcantara are all expected to pitch in Tuesday's intrasquad matchup.