Toronto's Jonas Valanciunas suffered a left ankle sprain when he was fouled by Philadelphia's Dario Saric in the first half of the Raptors' 128-84 win over the 76ers.
The Raptors announced he will be evaluated on a regular basis.
Valanciunas stayed in to shoot his free throws but was replaced about two minutes later and headed to the locker room. He did not return.
Valanciunas was coming off a strong season debut, scoring 23 points with 15 rebounds in Thursday night's victory.