Newcastle United and England goalkeeper Nick Pope suffered a suspected dislocated shoulder during the 1-0 win over Manchester United on Saturday.
He joins an already substantial Magpies injury list, with striker Callum Wilson and defender Dan Burn among those out.
"I don't know what the future holds for Nick, whether he'll need an operation or not," Howe told BBC Sport.
"It looks bad. It looks like a dislocation of his shoulder, which he has done before. He had it operated on and came back successfully.
"We'll get it checked out and fingers crossed he's back soon.