Everton manager Ronald Koeman says he wants to strengthen his squad in January following the news that forward Yannick Bolasie requires knee surgery.
Bolasie is travelling to London and is expected to have an operation next week after damaging ligaments in Sunday's 1-1 draw with Manchester United at Goodison Park
"It is a big loss for everybody, firstly himself, his team-mates and the club because he is an important player," Koeman told a news conference ahead of Saturday's Premier League trip to 11th-placed Watford.
"The operation will be next week. It is a big disappointment for everyone."
The Dutchman has been linked with a January move for United's Memphis Depay, but would not be drawn on potential targets.
"We are looking for some good options, maybe the (need) now is a little more than it was before because we lost Yannick for a long time.
"I don't speak about players, about rumours. We know that when January is coming of course every day in the press there is a lot of speculation.
"We need to do our work and don't mention it to the press."
Koeman said Bolasie's injury was an opportunity for other players in the squad to step up, but added that he wanted to see more productivity from the out-of-favour Ross Barkley.
The England international did not play against United at the weekend, and Koeman said the 23-year-old needed to prove in training that he was capable of earning back his place in the starting XI.
"He is one of the players who needs to bring more productivity," Koeman said. "And that's the talks we have about his situation, his chances to start and that's all.
"He did not play last weekend and that's the competition we have in our squad. If you like to play you need to show that to the manager the whole week and he is trying to do his best."
Seamus Coleman is fit for Everton, after being kicked in the head by United's Zlatan Ibrahimovic on Sunday.
Everton, who are searching for their first league win since October at Watford, are eighth in the table.