A free agent who was the NBA's Sixth Man of the Year in 2006-07, Barbosa was signed by the Celtics as a free agent last summer to back up Rajon Rondo while Avery Bradley recovered from shoulder surgery. Bradley has returned, but both Rondo and Barbosa are out with torn ACLs.
Barbosa averaged 5.2 points in 41 games in Boston.
Collins, an 11-year veteran, is known more for making contact than making baskets. Since the start of the 2006-07 season, he has 776 fouls and 554 points, including 74 fouls and 37 points this season.
AP Sports Writer Jimmy Golen in Boston contributed to this report.
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