Greg Taylor dealt Celtic an injury blow as he left the pitch against Ross County clutching his shoulder.
Less than 10 minutes into the second half at Parkhead, Taylor was replaced by youngster Adam Montgomery after going down in some pain.
The 23-year-old exited proceedings with the Premiership clash poised at 0-0 with a recurrence of an old injury.
The Scotland cap previously had a spell on the sidelines with a dislocated shoulder - an outcome boss Ange Postecoglou will hope to avoid.
While Montgomery was called upon to replace Taylor, new boy Liam Scales played on the left of the defence for former club Shamrock Rovers and may be an option for the Hoops headed into Europa League action next week.
The Glasgow men head to Spain next Thursday to take on Real Betis to open their group campaign in Seville - the city where the Hoops contested the 2003 Uefa Cup Final.
