6/19 13:23: Matt Gelb of The Philadelphia Inquirer says Mathieson was DFA’d to clear a spot for Dane Sardinha.

Mathieson was placed on optional waivers, a rare waiver rule.  Here’s Gelb’s explanation:

There are four types of waivers, the rarest being optional waivers. They are required when a team wishes to option a player who has options remaining but is more than three calendar years removed from his major-league debut. Mathieson falls under that category; he made his debut on June 17, 2006. And he has options left.

6/19 10:39: According to Matt Gelb of The Philadelphia Inquirer, the Phillies have designated Scott Mathieson for assignment. Gelb explains that Mathieson had options left, but assistant GM Scott Proefrock did not explain the situation, rather he said it was a procedural move.

Mathieson, 26, made one appearance for the Phillies this year. He went 2/3 of an inning and gave up three hits and two earned runs.