The Spurs made the announcement Wednesday. Udoka played sparingly in 20 games after being signed in November and logged just 3 minutes in Tuesday's loss at New York.
It was Udoka's second stint with the Spurs after spending two seasons in San Antonio following the team's last championship in 2007.
The Spurs' roster stands at 12. Rookie swingman James Anderson is expected back soon after missing the last two months with a stress fracture in his foot.
The NBA-best Spurs play Boston on Wednesday.