DETROIT -- The Tigers were hoping Casey Mize avoided a serious injury after the team’s top prospect left his start for Double-A Erie in the third inning Thursday night in Reading, Pa., and test results have eased their concerns.

Though Mize has been placed on the seven-day injured list at Erie, an MRI exam taken Friday morning suggested right shoulder inflammation rather than something more serious. Noted orthopedic surgeon Dr. James Andrews and Tigers team surgeon Dr. Stephen Lemos both reviewed test results and agreed on a diagnosis of minor inflammation in the back of the shoulder, according to the team.

It's a major relief considering the way Mize’s exit looked. His velocity had dropped in the second inning and continued into the third.

Mize did not move his arm after his 23rd and final pitch, a mid-80s cutter, taking the throw back from catcher Kade Scivicque and remaining in place as the catcher called for manager Mike Rabelo and head athletic trainer T.J. Obergefell. Mize did not attempt a warmup toss, instead leaving the field with Obergefell, as Rabelo signaled for reliever Nolan Blackwood.

Neither Mize or Rabelo talked with reporters after. Reading Eagle beat writer Mike Drago tweeted afterwards that Mize left the visitors' clubhouse without his shoulder wrapped, and he was able to lift his suitcase onto the team bus.

Injury is the one opponent that has been able to knock out Mize so far in his first full pro season. Last year’s top pick in the MLB Draft has lived up to the billing, maybe even exceeded expectations, by posting an 8-0 record and 0.92 ERA in 13 starts between Erie and Class A Advanced Lakeland. He has allowed just 42 hits over 78 innings with 12 walks and 75 strikeouts.

While general manager Al Avila has all but ruled out the possibility of Mize pitching in Detroit this season, his roll through the Minor Leagues raised discussion about promoting him to Triple-A Toledo, a move that seemed to be coming sooner than later.

That is now on hold. Even though Mize’s test results don’t suggest any structural damage, the Tigers are expected to use an abundance of caution before putting him back on the mound. He’s at 78 innings for the season, after throwing 128 1/3 innings last year between Auburn University and Lakeland. The Tigers normally prefer pitching prospects to not exceed their previous season’s innings by more than 25 percent to 30 percent, so an IL stint will allow them to limit that uptick.