Who Should Chelsea Sell?  (Sky Sports)

Chelsea's difficult season has been well documented, with the defending Premier League champions currently languishing in mid-table.

After bowing out of the Champions League on Wednesday, Guus Hiddink's side are left with the FA Cup as their final chance to salvage silverware.

The interim boss described the Blues as a team "in transition" after the defeat by Paris Saint-Germain, and with a change in manager expected at Stamford Bridge this summer, there's likely to be plenty of transfer activity too.

So we asked Sky Sports' Paul Merson which Chelsea players he would keep at the end of the season, and which he would move on ahead of next term...

Who should stay and who should go? Paul Merson says...

Stay                             Let go                Wait and see
Thibaut Courtois             Eden Hazard       Branislav Ivanovic
Cesar Azpilicueta           Oscar                 Gary Cahill
Kenedy                          Pedro
Kurt Zouma                    Loic Remy
Cesc Fabregas               John Obi Mikel
Nemanja Matic               Baba Rahman
Willian
Diego Costa
Bertrand Traore

I wouldn't necessarily say Chelsea are in transition, but they need to buy a lot of players. You look at McDonald's - they sell more cheeseburgers, more fries, and more soft drinks than any other fast-food chain in the world, but they still do adverts.

Chelsea won the league last season, but they didn't invest to keep them on top, and we saw the same problem a couple of years ago with Man City. You have to keep kicking on, and sometimes you have to upset players by bringing in others who are better.

Goalkeeper and defence

Looking at their squad, you'd keep the goalkeeper no question. Thibaut Courtois is the undisputed number one.

But I watched Baba Rahman the other week against Southampton and he was all over the place so I'm not sure he's at the right level. I like Kenedy, he's a good young player and I'd keep him at the club.

The way to look at it with Cesar Azpilicueta is, if Chelsea were to sell him, would top teams be in for him? They would be, so he should stay.

Moving onto central defence, John Terry leaving still shocks me because he's the main defender at the club.

Branislav Ivanovic has been poor this season and he's very fortunate to still be playing in the team. He was the best defender in the country last year but his confidence has dropped, and you see that happen to the best players.

With him, I'd wait and see how he plays over the first three or four games of next season and then make a decision very quickly. If he comes back and he's playing at his top level again, there's still a place for him. But if not, he'd have to go straight away for them to win trophies.

I'm not the biggest fan of Kurt Zouma in the world. He's quick across the ground but he's a bit rash. He's still learning the game but Chelsea don't have time for that, they need to win things. You'd still keep him, though.

If they're getting rid of Terry they have to buy a replacement in the summer, but who's about? You only have to look at Manchester City's signing of Eliaquim Mangala. He was the best part of £30m and you're not getting a lot for your money.

That is what worries me with Terry, because they can spend £20m or £30m but they're not necessarily going to improve. With Gary Cahill and Zouma at the back, for me they're not winning the Premier League next season.

Midfield

In midfield, Cesc Fabregas would get a club tomorrow morning. On his day he's brilliant, and since Jose Mourinho has gone he's decided to play. Against Southampton he was absolutely outstanding, and he's got that in his locker so keep him.

But would John Obi Mikel get a football match if Hiddink wasn't the manager? And how many top teams would put him in their side? I know he's done well since he's come in, but if you're looking to win the league I don't think you do it with Mikel playing 35 or 36 games.

Nemanja Matic is a strange one. He was one of the best holding midfielders in the world last season, but he's dipped, along with everybody else in the squad apart from Willian. I'd keep him because of what he showed the previous year, but I think Mikel could be on his way.

Then you get to Pedro, and it just shows you how good playing for Barcelona can make you look. He's had one or two decent games since he joined Chelsea but if I could get money back for him I would.

Willian has been the best player at the club by a million miles this season. He's been very good and all day long he should stay.

But I'd drop Eden Hazard off if I could get £60m for him. He's had one good year and this season he's been bordering on atrocious. If you can get the money, you'd take it all day long. You don't know if he will turn out to be a one-season wonder and you can't take that chance.

It just shows you why Ryan Giggs is held in such high regard, because he was so good for so long. His whole career he was eight out of 10. It wasn't nine out of 10 one year and then down to five out of 10 the next.

Oscar is in and out. One minute he's in the team and looks great, and then he's out of his depth and lightweight. I'd get rid of him if you can get good money.

Strikers

Diego Costa has started to perform now and he looks a proper player. For 60 minutes against PSG he had them in his pocket. He looked the player we thought he would be, and he wasn't worried about beating people up. Strikers like that don't come around too often and you have to keep hold of them.

Loic Remy should be gone, and you'd keep Bertrand Traore because he's one for the future, but they would need to buy another forward in the summer because it can't just be Costa.