Ali Omar is out of Torquay United's second game of the National League season at FC Halifax Town on Saturday after the clash of heads which saw him helped off near the end of the Gulls' opening-day 0-0 draw with Oldham Athletic.
The former QPR and Barnsley centre-back must serve a concussion 'protocol' after spending much of last Saturday night in hospital and then undergoing further examinations this week.
"Ali is out for this weekend at least, but he will be back pretty soon and we think we can cover that," said manager Gary Johnson, ahead of successive away games at Halifax and Bromley next Tuesday night.
Johnson has various options to replace Omar in the immediate future - he could switch from a back-three to a four or move midfielders Ryan Hanson or skipper Asa Hall into defence.
United have other injury problems.
They were already without Tom Lapslie, Aaron Jarvis, Shaun Donnellan and Dan Martin before the Oldham game, and then lost striker Corie Andrews (hip) and Omar during that match.
Andrews has a chance of recovering for this Saturday, but Johnson confirmed that the club is still searching for new options elsewhere.
"Our squad is not quite big enough yet - we need a couple more clubs in our bag, as we like to put it," he said.
Ex-Crawley and Southend winger Ashley Nathaniel-George, who made his debut off the bench against Oldham, remains on trial at Plainmoor.
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