Phillies pitcher Sean O'Sullivan (knee) will begin a rehab assigment with Class A Lakewood Thursday, the Philadelphia Inquirer reports.
O'Sullivan threw 50 pitches during a simulated game Saturday and appears ready to take the next step, taking the mound for a start Thursday. He made just two starts this season before hitting the disabled list, going 0-1 with a 4.91 ERA and 7:3 K:BB ratio in 11 innings.