Perez (knee) is going for a second MRI on Tuesday, MLB.com's Jeffrey Flanagan reports.
His MRI on Sunday showed no damage beyond inflammation, but either the Royals or the player were unsatisfied with the results, so he will go for a second test Tuesday. This suggests the knee issue is more than just a day-to-day ailment, but we won't know how much longer he will be sidelined until after the results are released.