Everton manager David Moyes hopes Kevin Mirallas will make a quick return to the side and said he had been "worried" by the Belgium international's injury problems.
Mirallas, 25, who has been plagued by hamstring injuries since late October, limped off 18 minutes into last Saturday's 2-1 FA Cup fourth-round win at Bolton.
The former Olympiakos man was making his first start since early December, when he had been forced off with the same injury during a win against Tottenham.
Moyes is wary of risking further aggravation of the problem by rushing Mirallas back, and will assess him before deciding how quickly to restore him to the matchday squad.
Asked about his side's injury situation ahead of Wednesday's Premier League clash against West Brom, the Everton boss said: "We're improving. We're a little bit worried about Kevin Mirallas. He came off, but I don't think it's as bad as maybe we thought."
Moyes is hopeful that midfielder Darron Gibson will be able to return against the Baggies after a month out with a thigh problem.
Gibson, 25, has suffered thigh trouble for much of the season, having spent almost three months on the sidelines after picking up an injury at West Brom on September 1. He found himself out again with a problem picked up over Christmas.
"We'd like to get Darron Gibson back," Moyes said. "He didn't quite make it for the Bolton game last weekend. He felt his thigh again last week. But he and Kevin are not as bad as they were a few weeks ago. They're not too far away."
Right-back Seamus Coleman will definitely miss the West Brom game as he recovers from the thigh problem that forced him off at Southampton.
"Seamus Coleman's got an injury that's probably going to keep him out for about four weeks in total," Moyes said. "So I would think he's got at least another couple of weeks before he's back fit."
Meanwhile, Everton are attempting to tie up a deal to sign Netherlands international Leroy Fer from FC Twente. Fer, 23, was on Merseyside on Tuesday to have a medical, and Moyes hopes to have good news to announce shortly.
"He's a really good player, but we have to say he's not signed yet," the manager said. "He's only part way through his medical, so there's a bit to go before we can confirm anything. I think it will be better if we talk once I get him signed."
Moyes, whose side are fifth in the Premier League, three points outside the top four, is wary of a West Brom team who have not been out of the top eight all season.
Steve Clarke's men, who were third in late November, have lost their way a little of late, falling to eighth after losing six of their last ten league games.
"I think they've done really well," Moyes said. "West Brom and Steve Clarke have got a really solid squad, with good players. I wouldn't say I've been surprised by them, but they've kept going and look as if they're set for a top-half finish."