Mastroianni (oblique) ran straight-ahead sprints at 75 percent and played catch at 90 feet out Tuesday, Mike Berardino of the St. Paul Pioneer Press reports.
He is making tangible progress from an oblique injury, but Mastroianni still has several important hurdles to clear. While he's also swung a bat underwater without issue, he will need to take dry swings and hit flip-toss before progressing to batting practice and ultimately a rehab assignment.