Leiter returned to Philadelphia to undergo testing for forearm tightness, Matt Breen of The Philadelphia Inquirer reports.
It's not a good sign for Leiter, who was likely to open the season as the Phillies' long reliever with a shot to move into the rotation later in the year. Forearm tightness is sometimes a precursor to more serious arm trouble, though there have been no indications yet from the team the underlying cause is a severe one.