The 18-year-old was later diagnosed with a torn ulnar collateral ligament and paid a visit to renowned surgeon Dr. James Andrews. Surgery hasn't been recommended just yet, but there's a possibility that it will be in the near future.
"Right now they said just to give him a few days and start playing catch," general manager Alex Anthopoulos said. "He's going to throw to 60 feet [today]. Right now it's basically rest and rehab. But there is a scenario if he does have a flare-up again in the next few weeks that ultimately he may need Tommy John."
Osuna ranks just behind promising right-hander Aaron Sanchez on the club's depth chart for pitching prospects. He has a plus fastball that can hit the mid-90s with reportedly very strong command.
The native of Mexico still needs to work on his slider, but all of his skills are very advanced for someone his age. The club may prefer to get the surgery out of the way now so it doesn't have a negative impact on his development during the later stages of his Minor League career.
Osuna was 1-2 with a 3.63 ERA in five games for Lansing this season.
Gregor Chisholm is a reporter for MLB.com. Read his blog, North of the Border, and follow him on Twitter @gregorMLB. This story was not subject to the approval of Major League Baseball or its clubs.