Butler appeared in 46 games for the team this year, averaging 2.7 points and 1.2 rebounds per night.
The 36-year-old had a limited role in San Antonio, playing 9.4 minutes a game—the third-lowest of his 13-year NBA career.
Jeff McDonald of the San Antonio Express-News believed the Spurs made this move in order to open a roster spot for shooting guard Kevin Martin, and the team subsequently confirmed the acquisition. Martin would certainly be a better option off the bench as San Antonio looks to close the gap on the Golden State Warriors, who are three games up in the standings.
Teams won't be clamoring to sign Butler, especially since the March 1 deadline has passed to ensure a player who was waived is eligible for the playoffs. That could narrow his options somewhat.
However, he's a career 36.2 percent shooter from beyond the arc, and he has appeared in 43 postseason games. Butler can't play in the playoffs this year, but he could find a way to use his previous experience in them to help his teammates in other ways.
If Butler is unable to sign with anybody before the end of this year, then his NBA career could very well be over.