3:06pm: Mathieson has been placed on optional waivers, according to Gelb. Assistant GM Scott Proefrock is hopeful that the club will be able to retain the righthander. Because optional waivers are revocable, they should be able to keep him in the organization.
12:36pm: Gelb confirmed with assistant GM Scott Proefrock that Mathieson was indeed designated for assignment even though he has minor league options remaining (Twitter link). Proefrock said it was a "procedural move," but would not elaborate.
12:13pm: The Phillies have designated reliever Scott Mathieson for assignment, tweets Matt Gelb of The Philadelphia Inquirer. The move frees up a roster spot for catcher Dane Sardinha, who was recalled from Triple-A.
The 26-year-old Mathieson appeared in just one game for the Phillies this year, giving up two runs while recording just two outs against the Twins yesterday. The two-time Tommy John surgery survivor struck out 34 batters in 29.2 innings in Triple-A this year, and is best known for a fastball that flirts with triple digits.