MINNEAPOLIS -- Tyler Glasnow won’t be back with the Rays when he is eligible to come off the 60-day injured list on July 10.

The club's initial hope was for Glasnow to rejoin the team after the All-Star break, which is when the right-hander would become eligible to come off the injured list. But after suffering a setback on Sunday in Oakland, Glasnow’s future this season became a lot less clear.

On Monday, the Rays announced that Glasnow felt discomfort while throwing from 90 feet. An MRI revealed right flexor inflammation, and Glasnow has been shut down from throwing for three weeks. He will then be re-evaluated.

“It’s disappointing, there’s no doubt,” Rays manager Kevin Cash said on Tuesday. “Look, he was the best pitcher in baseball before he got hurt. I’m not saying he is the best pitcher, but he was performing as a top pitcher, if not the best. When you get that kind of performance and you don’t have it, it’s disappointing.

“You never want to lose one of your better guys, but you want to rally around it a little bit together and find ways to pick him up while he’s down, and hopefully we get some good news in three weeks and resume his throwing and see how quickly we can build him back up.”

Losing Glasnow for at least another month is a big blow for the Rays, who saw getting the right-hander back from injury as a huge addition, as they contend for a postseason spot.

Over the first month of the season, Glasnow was arguably the best pitcher in the American League, earning AL Pitcher of the Month honors in April after posting a 5-1 record with a league-best 1.86 ERA over eight starts.

With Glasnow out longer than expected, the Rays will lean on Blake Snell, Charlie Morton and Yonny Chirinos for most of the team’s starts moving forward, with Jalen Beeks and Ryan Yarbrough also contributing as the club’s primary bulk-innings pitchers.

“We’re still going to use openers in front of Yonny and in front of Yarbrough and Beeks on given days when it works,” Cash said. “With Glasnow, Charlie and Blake -- it was that much more versatile. We’ve got to check ourselves a little bit, see where the bullpen is at on given days. I think Yonny in his opportunity as a starter has been outstanding. If that’s the route we want to go, we’re going to do that.”

The Rays also announced that reliever Diego Castillo has been diagnosed with right shoulder impingement and will be sidelined for about two weeks. Castillo has been a big part of the Rays bullpen this season, but the right-hander has struggled mightily, posting a 14.40 ERA in six appearances this month. He was placed on the injured list on June 23 after allowing a combined six runs in back-to-back outings in Oakland.

Infielder Daniel Robertson also underwent arthroscopic surgery Monday on his right knee to remove a loose body. The procedure was performed by Dr. Koco Eaton in St. Petersburg. Robertson is expected to miss four to six weeks with the injury.

Diaz update
Yandy Díaz is close to returning to the lineup. The infielder said he’s feeling much better with his right hamstring injury, and he hopes to be in the lineup on Thursday, which is when he’s eligible to come off the 10-day injured list. Diaz went through infield drills and batting practice on Tuesday.

“He’s going to have a normal day today, and we’re hopeful that he’ll be back in the lineup on Thursday,” Cash said. “Two more days need to take place of him feeling good, but talking to him on Sunday on the plane, he was in a better spot saying that his hamstring felt much better, so that’s a good sign. We’ll get through today, get through tomorrow and see if he’s ready to go for the day game on Thursday.”

Alvarado continues his progression
José Alvarado continued to go through his pitching program at the Rays’ Spring Training facility in Port Charlotte, Fla., and the Rays could get their top reliever back during their next homestand, which begins on Friday against the Rangers.

“[We're] expecting him to join us over the homestand at some point,” Cash said. “We need him, that’s for sure. We’re doing everything we can to get him back, because he’s a big weapon to our bullpen that we need sooner than later.”

Minor matters
Eighteen-year-old phenom Wander Franco, MLB Pipeline's No. 1 overall prospect, was promoted to Class A Advanced Charlotte. The shortstop was in the lineup on Tuesday in Port Charlotte and went 2-for-3 with a walk. Franco slashed .318/.390/.506 with six home runs in 62 games with Class A Bowling Green. He struck out just 20 times in 233 at-bats for the Hot Rods.

Shortstop Taylor Walls has also been promoted to Double-A Montgomery after slashing .269/.339/.417 in 41 games with Charlotte.

The Rays also signed outfielder Izzy Wilson to a Minor League contract and assigned him to Bowling Green. The 21-year old outfielder was recently released by the Braves.