Missouri forward Jontay Porter, who missed his entire sophomore year in 2018-19 after tearing his right ACL during the preseason, re-tore the ligament, the Tigers confirmed to the Kansas City Star's Alex Schiffer.
Sources told Schiffer that Porter suffered the injury during rehab work in Denver.
Jontay hasn't declared for this June's NBA draft yet. The 6-foot-11 forward was last projected as a late first-round pick. Last season, he returned to Mizzou after a poor showing in the draft combine.
His brother, Michael, missed all but three games in his lone season at Missouri in 2017-18 due to a severe back injury. Despite that, he was selected 14th overall by the Denver Nuggets last June. A second back surgery last summer has kept him inactive for this entire season.