Ole Gunnar Solskjaer says Manchester United will miss Marouane Fellaini's "X factor" for up to a month after the divisive midfielder sustained a calf injury.

Having been a key component under Jose Mourinho, speculation has mounted about a January exit as the Belgium international has managed just 31 minutes since the Portuguese's exit.

But Fellaini, who signed a new contract until at least 2020 in the summer, looks set to stay at Old Trafford after suffering an injury setback and earning praise from caretaker manager Solskjaer.

"He'll probably be at least three or four weeks (out)," the United boss said of the 31-year-old, who joins Chris Smalling and Marcos Rojo on the sidelines.

"He's got a calf problem and that's sad because there's X factors in different players and we all know Felli's X factor.

"Then again, he'll be working hard to get back in when all the big games are coming as well."

Solskjaer does not expect Scott McTominay to leave on loan and confirmed the club are in contract negotiations with the midfielder, while the United boss confirmed January arrivals are unlikely.

The main focus now, though, is Saturday's match against Brighton. Eric Bailly is back from suspension for the match and Alexis Sanchez is available after missing last weekend's 1-0 win at Tottenham after a hamstring issue flared up.

"I love it to be fair," Solskjaer said. "I have to say I look forward to getting up in the morning to start work again, I always do in football.

"Molde, Cardiff, I love working with people, trying to improve people and when you are here you want to go to bed at night and get up in the morning again.

"I'm still in the hotel but I've found a place, so I won't be too long. I've been driving around a bit to find my bearings again.

"I've got mates here, so I have been to see a few of them so it's not like I'm stuck in the hotel on my own."