San Antonio currently has a full roster of 15 players, so they will need to waive someone to make room for Miller. Matt Bonner and Rasual Butler, both on minimum contracts and out of the team's rotation, are likely candidates.
Miller, a former near-all-star, has appeared in only 26 games so far this season, averaging 3.4 points and 2.2 assists. For his career, Miller is 20th all-time in games played 1291, and ninth overall in assists (8495).
Despite his long and prolific tenure in the NBA, Miller has had virtually no playoff success. His sole playoff series victory came in 2014 as a backup point guard for the Washington Wizards. The decision to sign with the Spurs is likely a last ditch effort to play in an NBA Finals in the twilight of his career.
Miller will be re-uniting with LaMarcus Aldridge in San Antonio. The two played together in Portland for two seasons from 2009 to 2011, and had a notable rapport on offense:
LaMarcus Aldridge's career spiked when Andre Miller came to Blazers and starting throwing him lobs. Bet he's one of biggest fans of signing— Jason Quick (@jwquick) February 27, 2016
While with the Blazers, Miller famously exploded for 52 points in January 2010 against the Dallas Mavericks. The performance tied Brandon Roy for the second most points in a game in franchise history.
The Blazers traded Miller to the Denver Nuggets for Raymond Felton in 2011.