Beram Kayal sustained a facial injury during Celtic's 2-0 friendly win over Perth Glory in Australia.
The Israeli, who missed the end of last season with a fractured wrist, took a heavy blow to the nose as he was accidentally caught by an elbow.
After being unable to stem the blood flow, Kayal was replaced by Shaun Maloney before half-time.
Gary Hooper and Charlie Mulgrew scored Celtic's goals as they claimed their first pre-season victory.
Recent signings Kelvin Wilson and Adam Matthews featured for Neil Lennon's side while the Glory line-up included former Celtic and Hibernian midfielder Liam Miller.
Celtic complete their Australian tour against Melbourne Victory on Wednesday.