Templeton and fellow-forward Andy Little were crocked in the Light Blues' win over Airdrieonians last Wednesday and scans have shown they are facing several weeks on the sidelines.
Ally McCoist's side face Raith Rovers on Sunday, April 6, at Easter Road and host Dundee United in the William Hill Scottish Cup semi-finals the following Saturday.
McCoist said: "We've had a couple of scans on Little and Templeton which didn't bring great news, so they look like they might be three or four weeks, rather then just missing one or two games.
"It'll be round about [the semi-final] period, so obviously it would be great if they are back and fit for it, but it looks at this moment in time as if it's touch and go.
"No, I wouldn't say [it's a no]. They are both really, really keen to play and keen to get fit.
"I would give them every opportunity.
"I was obviously just disappointed the results didn't say it was a slight strain that would have resulted in a couple of weeks, but I am absolutely not ruling them out."
Youngster Lewis Macleod has not played for the League One champions since January 25 and was back in hospital yesterday for more checks.
McCoist said: "It's a viral issue he's seeing the doctor about for an update so the next time I speak I'll hopefully be better qualified to give people some good news which would be great."