The 28-year-old has only played 19 minutes of football since March due to a knee problem. He made a brief appearance off the bench in Northampton's play-off semi-final victory at Cheltenham in May before undergoing surgery.
Boothroyd has admitted it was a mistake to risk him, one which is costing his struggling side with the Cobblers rooted to the foot of League Two.
"We rushed him and that's had a big detrimental effect on him. We're paying the price for that," Boothroyd said.
"I wouldn't want to put him under any pressure but we're now talking next year, definitely."
Langmead, who was Northampton's Supporters' Player of the Season and Players' Player of the Season last term, will need to prove he is fully fit before he makes his comeback.
"We've got to make sure he's 100 per cent and when he is ready to come back, that we've done everything we can to make sure he doesn't break down again," Boothroyd added.
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