PHILADELPHIA (CBS) – When Roy Halladay decided to call it quits in December, he became the first member of the best pitching staff in Phillies history to retire. There will now be a pair of aces who will no longer be in the dugout.

Former Phillies pitcher Roy Oswalt has decided to retire, according to ESPN’s Buster Olney.

Oswalt will work with his agent, Bob Garber.

In one and a half seasons with the Phillies, Oswalt went 16-11, with an ERA of 2.96. Oswalt went 163-102 in his 13 year MLB career, the majority of which was spent with the Astros (10 years). The Phillies traded for Oswalt in 2010, in a deal that included JA Happ, Anthony Gose and Jonathon Villar.

Oswalt went 0-6 with the Rockies in 2013, with an ERA of 8.63.