The 27-year-old suffered the setback while on loan at Leeds United, bringing a premature end to his stay at Elland Road, which had been scheduled to continue until January.
And Leeds' assistant manager Nigel Gibbs was disappointed to see Blackstock's short stint brought to an end.
"He fitted in really well and you can see from his performances how much he brought to the team," Gibbs told Leeds' official website.
"We are sad to see him go back. He came on as a sub in the first couple of games but then he played his part in the team. He really knitted the team really well and had a good relationship with Ross (McCormack) up there.
"We never really saw the best of him but he contributed while he was here and I think he could have done really well for us."
Blackstock, who has also had spells at QPR and Southampton, scored once in four appearances for Leeds Brian McDermott's side.
