Calf and ankle problems delayed his debut until the Boxing Day win over Coventry but he limped out of the New Year's Day loss at Bristol City.
"We've sent him away for three or four days, the boy is totally distraught," said Cardiff boss Dave Jones.
"It looks a bad tear in the hamstring so you're looking at eight to 10 weeks I would think minimum on that.
"He's worked so hard to get back and was doing really well. It's always the secondary injuries, it's never the one you had long-term.
"We'll pick him up and dust him down and try and get him going again."
Jones' patched-up backline performed superbly on Saturday to earn a 1-1 draw at Stoke City in their FA Cup third-round match, booking a replay at the Cardiff City Stadium on Tuesday, 18 January.
Should they beat the Premier League side then a fourth-round trip to Doncaster Rovers or Jones' former side Wolverhampton Wanderers awaits on 28-30 January.
But the Bluebirds boss admits he needs to strengthen his squad further, after signing striker Jon Parkin from Preston North End.
"I'm always optimistic of getting something in but it's such a hard time, the January window," Jones added.
"Everybody wants to get into an auction, everybody doesn't want to let the players go before they've got players in or see what comes in on the deadline.
"It's always difficult but we'll soldier on."
Source: BBC Sport