The 6-foot-7 inch, 225-pound Finley, a two-time All-Star, averaged 15.7 points and 4.1 rebounds per game last season for the Dallas Mavericks. He was waived in August as a cost-cutting measure.
"We are extremely pleased to have a player of Michael's caliber joining our franchise," said San Antonio Coach Gregg Popovich on the Spurs' Web site. "He brings an All-Star level of talent to the floor and a high degree of character to the locker room."
Finley, 32, has averaged 19 points, 5.1 rebounds and 3.7 assists per contest in 735 regular season games for Dallas and Phoenix. In the post-season, he has played in 56 games and averaged 17.8 points and 5.2 rebounds per contest.
Finley was the 21st overall pick in the 1995 NBA draft by the Suns and was obtained by Dallas in December 1996.