Everton manager Ronald Koeman has warned supporters not to expect to see Yannick Bolasie return to the first-team until 2018, as the winger prepares for a second knee operation.

The club paid Crystal Palace £25m for the 27-year-old in August, only £3m less than they paid Chelsea for club record signing Romelu Lukaku.

The DR Congo international made a bright start to his career at Goodison Park, scoring once and making four assists, but limped out of the 1-1 draw with Manchester United in December after rupturing the anterior cruciate in his right knee, in a tussle with Anthony Martial.

Bolasie was instantly ruled out for the rest of the 2016/17 season and underwent surgery to repair the meniscus in his knee.

However the surgery revealed the damage was more significant than first feared, necessitating a second operation as well as extensive rehabilitation.

The operation means that Bolasie will be ruled out for the rest of the calendar year.

Bolasie was injured in a collision with United's Martial (Getty)

“The surgery was expected because his first surgery was about his meniscus, now what will happen at the beginning of March is about his cruciate,” Koeman said in his press conference, ahead of Everton’s home match against Sunderland on Saturday.

“It is difficult to put a time scale because normally a cruciate can be six, seven, eight months,” he said.

"We had to repair the meniscus and then wait until his knee was ready to have the second operation.”

Koeman praised the positive attitude of the player (Getty)

Koeman also praised the mentality of the winger, who he claims is remaining positive despite this latest setback.

"He was several times in during the week, he was ok, really positive, working hard to come back but like every player in that situation you get difficult moments in a day, difficult moments in the week," he added.