Memphis opens its regular season against Utah at FedExForum on October 21. That game falls before the end of a two-week window measured from Friday's announcement. The Grizzlies' next preseason game is October 16 against Charlotte, according to the official team schedule.
CBS Sports' RotoWire report said Stewart is likely to miss opening night and identified Quinten Post as a possible backup-center option behind Zach Edey while Stewart is unavailable. That is an assessment of the rotation, rather than a lineup commitment announced by Memphis.
The timing matters for a player still establishing his place with a new club. Memphis acquired Stewart from Detroit in June for three future second-round picks, a transaction reported by ESPN's Shams Charania and recorded on Stewart's NBA player page. The 25-year-old had spent his NBA career with the Pistons before the move.
For now, the confirmed information is limited to the sprain and the next medical check. Memphis has not announced a firm date for Stewart to resume games. His progress through that reassessment will determine when the Grizzlies can work him back into their regular-season frontcourt.