Wigan boss Roberto Martinez has revealed defender Adrian Lopez could be sidelined for 10 weeks with the hamstring tear he suffered in Saturday's defeat at Norwich.
James McCarthy's ankle problem, sustained in the same game, appears to have been only a short-term setback, but for Lopez the verdict was far from encouraging.
Martinez told the Wigan Evening Post: "We are waiting on the results of another scan, but Adrian has a tear to his hamstring and it will probably be between six and 10 weeks."
He added: "It's a shame because Adrian has never had a soft-tissue injury before. He is a sprinter and he has a real sprinter's muscles - you don't usually see people like him picking up this kind of injury."
Midfielder McCarthy had to be substituted at half-time at Carrow Road after being left with a hurt ankle following what Latics manager Martinez branded a "nasty challenge".
Martinez has since received an update on McCarthy's situation, and said: "We've had the scan and he has a sprain in his ankle, and we need to see how that develops.
"Any sort of injury is disappointing, although we are relieved that it is not a really bad tear to his ligament.
"He's been working really hard this past two days, accelerating the recovery process, but it's too early to tell if he'll be okay for the weekend."
Wigan, who have dropped into the relegation zone, play Arsenal in the Barclays Premier League on Saturday.
Defenders Gary Caldwell, Ivan Ramis (both hamstring) and Antolin Alcaraz (groin) could return, while midfielder Ben Watson, who fractured his shin in November, is to have his cast removed on Thursday.