Georgetown forward Otto Porter has ''symptoms indicative of a mild concussion'' and will sit out the Hoyas' game against Liberty.
Georgetown says before Wednesday's home game that Porter is being monitored by team doctors.
The sophomore is being evaluated daily.
Porter was hit in the head in the first half of Georgetown's 61-55 victory over Duquesne on Sunday.
He was the Hoyas' leading returning scorer from last season, when he averaged 9.7 points.
With top player Otto Porter Jr. sitting out because of concussion symptoms, Georgetown got a career-high 18 points plus nine rebounds from Greg Whittington and had very little trouble beating Liberty 68-59 Wednesday night.
Nate Lubick added 13 points and eight rebounds, and Mikael Hopkins scored 13 for Georgetown (2-0).
Liberty (0-3) was led by Casey Roberts' 13 points.