Southend United will be without Barry Corr until at least the latter part of the season, after the striker underwent surgery on an ongoing knee injury.
Corr, 26, who has been sidelined since pre-season, had the operation after suffering a setback in his recovery.
"Gilbert's struggling with a groin, Phillips a hamstring," he said.
"We might have paid the price with those two. But we'll cross that bridge when we come to it."
Victory against North End earned the Shrimpers a second round tie against Oldham and extended their unbeaten run to 15 games.
But Sturrock continued to issue caution ahead of the weekend visit of Bristol Rovers: "They will be smarting after a disappointing result on Saturday [a 2-0 loss to Barnet].
"We're going to have to get ourselves ready and rested for the challenge on Saturday."
Regarding Corr's injury, physio Ben Clarkson told the club website: "Barry has had some excess tissue removed from inside his knee and also had a micro fracture procedure along with a clean of his tendon.
"Everyone is hopeful that he will be back before the end of the season."