DETROIT -- The Tigers have two open spots in their rotation. Whether top pitching prospect Casey Mize will fill one of them is now up for speculation.

Detroit placed struggling starter Iván Nova on the 10-day injured list with right triceps tendinitis Saturday, a day after he gave up eight runs over 3 1/3 innings in a 10-5 loss to the Tribe. Right-handed reliever Anthony Castro was recalled from the alternate training site in Toledo, Ohio, to take Nova’s place on the roster.

What the Tigers will do with Nova’s rotation spot when it comes back around Wednesday against the White Sox in Chicago isn’t clear, but they’ll have another spot to fill. Tyler Alexander, who started last Tuesday against the White Sox, will piggyback Michael Fulmer's start Sunday against Cleveland after Daniel Norris pitched in relief of Nova on Friday night.

“There’s a lot of talk going on right now trying to figure out a rotation,” Tigers manager Ron Gardenhire said. “It’ll all get straightened out. We’ve had multiple conversations and we’ll continue to have them and they’ll do the right thing.”

Nova, signed in January to be a veteran innings-eater in Detroit’s rotation, has a 1-1 record with an 8.53 ERA in four starts. He has not shown his usual form, particularly in his last couple starts. Nova gave up four balls with exit velocities over 102 mph, including a 462-foot home run by Cleveland slugger Franmil Reyes off a hanging curveball on an 0-2 count.

“After the game yesterday, I felt a little sore, and I told the trainers,” Nova said. “They said to check it out, and I found out I have a little tendinitis in the tricep.”

Nova said he felt good during the game.

“It’s nothing too big. It’s a little tendinitis,” Nova said. “We’ve got a couple days to work it out and I’ll hopefully be back on the mound soon.”

Last Saturday, Nova allowed five runs in as many innings in Pittsburgh, where he battled his command as the outing went along.

For the season, Nova has surrendered 18 runs on 22 hits over 19 innings. Potentially more worrisome, he has as many walks as strikeouts (nine). Nova's expected numbers in batting average, ERA and slugging percentage are all in the bottom six percent among Major League pitchers this season.

Castro, the Tigers’ 19th-ranked prospect according to MLB Pipeline, gives Detroit some bullpen depth after the team used four relievers following Nova on Friday night. The first of them, Norris, threw 32 pitches. Gardenhire initially said afterwards that Norris would still be able to pitch Sunday. He backtracked on that Saturday.

“We’ll probably use Alexander now because we need length,” Gardenhire said, “and we’ll go from there. We’re working on this rotation. It’s all over the place right now. There’s all kinds of things happening here.”

By not pitching Norris on Sunday, the Tigers could potentially have him in line to fill one of the rotation voids next week. But that still leaves one opening to fill, and unless Detroit wants to use two short-outing starters in a three-day span, it will need to bring up a starter.

If general manager Al Avila chooses the latter, he might have little choice but to bring up Mize for his Major League debut. Mize, the former top overall pick and No. 8 prospect on MLB Pipeline’s Top 100 list, made a big impression in Spring Training and reinforced it in Summer Camp before being sent to Toledo.

Avila told MLB Network Radio on Friday morning that Mize and Detroit’s other highly regarded pitching prospects needed more work before getting the call. But that was before the Tigers' rotation went into flux.

Mize has been throwing in simulated games at Toledo.

“All I’ve seen is video,” Gardenhire said. “I do what they tell me. I’ve got enough up here. When it’s his time, I’m sure Al Avila will let you guys know.”