Alvarez, acquired from the Blue Jays in November, was shut down at the end of Spring Training with right shoulder inflammation. He is expected to take on a major role in the second half -- and in the future -- for the Marlins.
"I'm very excited," manager Mike Redmond said. "There will be a lot of evaluation. When we talked in Spring Training, we were hoping that we'd have had all these guys together initially in April and May. It hasn't worked."
Only Ricky Nolasco and Jose Fernandez remain from the Opening Day rotation. Rounding out the starting five are Alvarez, Nathan Eovaldi and Jacob Turner.
Heading into Spring Training, the Marlins anticipated those three being in the rotation. But Alvarez and Eovaldi were each on the DL with shoulder inflammation, and Turner opened at Triple-A New Orleans.
How long Nolasco remains with the club remains up in the air because he's been the subject of trade talks. And the Marlins are expected to deal the 30-year-old by the July 31 non-waiver Trade Deadline.
The Marlins have been one of the hottest teams in the game since their rough April and May.
Actually, since May 31, the Marlins are 18-11. Only the Red Sox (19) have more wins. But Miami and Pittsburgh share the best winning percentage (.621) in that span.
The Marlins are striving to build around power pitching. Eovaldi and Fernandez each throw in the upper 90s.
Fernandez, 20, and Turner, 22, are the youngest of the group. Both are rising talents, and represented by agent Scott Boras.
"With a lot of our guys, we're trying to decide which guys are going to be here for the future, and which guys are going to be part of the plan to get this organization back to where we want it to be," Redmond said. "We will be watching the guys. You're always pitching for something. You're always pitching to either stay in the big leagues or pitching for a contract, whatever it is.
"Right now, he's come over in this trade. There are a lot of uncertainties with Alvarez. We don't know what he's going to do. Our job is to evaluate and get him out there and see what we've got. ... He is a guy with good stuff."