Southampton midfielder Morgan Schneiderlin will miss the rest of the season because of a knee injury, but manager Ronald Koeman sees no reason to believe he has played his last game for the club.

The Frenchman suffered the problem during the 2-2 draw against Tottenham last weekend, with scans revealing the recovery time would sideline him for up to a month.

Schneiderlin had played a central role in Saints' promising campaign, which had earlier seen them up in the Champions League places.

The 25-year-old's performances have seen him linked with a summer move away from St Mary's Stadium, with the likes of Tottenham and Arsenal reported targets, although the club insists he is not for sale.

"He is a key player, so it is disappointing," said Koeman. "It is the ligaments of his left knee and that is a shame because he's out for the last part of the season."

It has been suggested Schneiderlin wants to secure a summer move to a Champions League club.

Koeman added: "He is happy (here), but it is up to the player.

"We like to keep everybody but we know sometimes it's difficult. But there isn't any serious bid for the player."

Southampton are also keen to tie up defender Nathaniel Clyne on a new long-term deal, the player having been linked with a big-money move to Manchester United.

"We are still speaking with Clyney and his agent, but we have to know it in 10 days now. The club is doing and offering the maximum we can do, then we expect the decision of the player," Koeman said.

"I have spoken to Clyney. He is very happy. Maybe there is some interest, I don't know because nobody has really had a bid for the player, but if I read the press then maybe there is some interest."

Koeman added: "All the players in the Southampton team are happy with how the team are doing but it is football, you never know.

"It is all about interest. We do everything to keep everybody in the team but it is difficult."

Asked what would happen if Clyne did not sign a contract extension past the end of the 2015/2016 campaign, Koeman said: "You know in football if you go in the last season of your contract, we don't like that. I think that is my answer."

Southampton head to relegation-battlers Sunderland on Saturday looking to maintain hope of European qualification, currently in seventh place but only a point behind both Spurs and Liverpool.

The Black Cats were thrashed 8-0 at St Mary's in October.

Koeman, though, is not expecting another walk in the park against a team fighting for survival under new head coach Dick Advocaat.

"It was the best result (but) it wasn't the best game in my opinion," said Koeman, who played under Advocaat when in the Holland national team.

"We had an unbelievable help of the players of Sunderland because I think they scored three own goals.

"After 2-0 or 3-0 they went mentally down, and we had total confidence and we scored great goals but the game of this Saturday will be totally different.

"It will be different for Sunderland because they are fighting and I am watching the programme and they play Arsenal and Chelsea, and they have two home games and they need two wins and that's a lot of pressure of the club and the players and we have to be aware of that."

Midfielder Dusan Tadic will, though, miss the trip to the north east because of concerns over a groin problem.

Koeman said: "We decide now to put him out of the team because he has to recover and be 100 per cent and, if not, he will struggle next season and we don't want that."

Victor Wanyama will be available again following suspension at the Stadium of Light, so Toby Alderweireld could drop back into defence.