"He has been a huge miss for us," said Wilder. "He was outstanding since his transfer last season and he's a game-changer. He's got raw pace and offers something out of the ordinary.

"We are looking for game-changers in the group. One of my criticisms is that we've not taken big chances and delivered in big moments, to change tight games. And Lys comes into that game-changer category and we're delighted to have him back.

"It's a huge boost for us. I think you saw the effect of John Fleck in the team on Sunday on everyone around him. It's been the same with Lys, he's lifted the place and we want all our big players back. He's certainly a big player for us."

The Blades were a revelation last season but have struggled so far this campaign, with Wilder's team bottom of the table with only one point from nine matches.

A combination of factors, chiefly the absence of defender Jack O'Connell to injury, has nullified the effectiveness of United's innovative 3-5-2 formation – which took them close to qualifying for Europe last season, before the Covid-19 pandemic hit.

A growing number of Blades fans believe Wilder should consider adapting their approach, perhaps to a back four, in light of the loss of O'Connell.

However, the United boss maintains his belief in what they are doing, saying: "We believe in it, it's worked for me for a long period of time.

"We're always assessing and analysing and we have to believe that the next game is the one that turns it around. I don't believe a wrecking ball is needed.

"It might be if we were all over the place and getting beat three or four. But if we'd have won the game on Sunday (against West Ham) I don't think people would have been scratching their heads."

The Blades have fitness concerns over Enda Stevens and one other player, who Wilder declined to name, ahead of the trip to the Hawthorns to face West Brom – the team immediately above United in the table.