Philadelphia, PA (SportsNetwork.com) - The Philadelphia Phillies activated pitcher Sean O'Sullivan from the 15-day disabled list to start Tuesday's game against the Pittsburgh Pirates.

O'Sullivan landed on the disabled list in mid-April due to left knee tendinitis. He last started on April 17, when he allowed four runs and a pair of homers in a loss at Washington.

Over two starts this season, O'Sullivan has posted an 0-1 record with a 4.91 ERA in 11 innings.

He is 0-8 in his last 17 major league games (12 starts) and has not won since May 12, 2011, while then a member of the Kansas City Royals against the New York Yankees. His losing streak is tied for the longest active one in the majors.