Boss Dean Smith admitted Aston Villa are unlikely to sign a striker before the visit of Manchester City.
They host the Premier League champions on Sunday without a fit senior forward and sit just one point above the relegation zone.
Jonathan Kodjia is likely to miss out through illness with Keinan Davis (hamstring) also sidelined.
Villa are looking for a forward after Wesley's season-ending knee injury on New Year's Day but, having been interested in Chelsea's Olivier Giroud and Michy Batshuayi, they remain frustrated.
Smith said: "We're working on it all the time, do I think we'll have it before Sunday? No.
"We're working around the clock to bring players in but it's a narrow window and a lot of clubs don't want their better players to be leaving.
"When you are after players, four things need to align, the selling clubs want to sell, the buying club wants to buy and have the funds and then the player and his agents.
"There are four boxes and we're not any closer to doing that at the moment."
Villa are also searching for a goalkeeper with Tom Heaton out for the season with a knee injury and have been linked with former Liverpool star Pepe Reina, currently at AC Milan.
But Smith backed stand-in Orjan Nyland, who played in Wednesday's 1-1 Carabao Cup semi-final first leg draw at Leicester.
He said: "I'm confident in his ability, when I first came he was number one and playing well. He saved a penalty at Swansea and then snapped his Achilles so was out for six months.
"In that time we brought in other goalkeepers. We recalled Jed Steer (from Charlton) who helped us get promoted and unfortunately he has done his Achilles and Tom Heaton, who got injured against Burnley.
"He has worked very hard to get to the levels we expect and he can play at this level."
Danny Drinkwater is expected to be in the squad after his loan move from Chelsea.
The midfielder has made just two appearances this season while on loan at Burnley.
Smith added: "He's a talented player, holds a medal for a Premier League champion but his career has stalled with his move to Chelsea not going as he would have liked.
"He's a winner, we spoke a lot in the dressing room about what it took to get promoted last season.
"It takes that winner's mentality and player with the experience he has got can only help the dressing room."