Birch (knee) has been ruled out for Sunday's game against the Mavericks, Jeff Garcia of KENS 5 San Antonio reports.
Birch was acquired by San Antonio ahead of the trade deadline, but he never made any appearances for the Spurs while battling a lingering knee injury. He made 20 appearances for the Raptors this season, posting 2.2 points and 1.3 rebounds in 8.1 minutes per game.