Manchester United manager David Moyes has questioned whether some of his players' best is good enough for the club to salvage their season.
United have lost their last three matches in all competitions and head into Saturday's Premier League meeting with Swansea City 11 points behind leaders Arsenal.
The champions' poor form has led to questions about the quality of the squad at Moyes' disposal, and the Scot has hinted at his concerns.
“I think a lot of them are giving their best, but if that is not enough, it is something I need to have a look at,” Moyes said in The Times.
Moyes is currently without key strikers Wayne Rooney and Robin van Persie, the former struggling with a groin problem and the latter a thigh injury.
Rooney has been sent for warm-weather training in a bid to aid his fitness ahead of a crunch meeting with Chelsea on Jan. 19, but it remains to be seen when Van Persie will return.
“We are hoping Wayne will be fit for that [Chelsea],” Moyes said. “We just want to nip it [the injury] in the bud and see if we can get on top of it.
“We are trying to get Robin back but it’s a thigh strain similar to the one he had at Arsenal so we are having to manage it correctly. There are some injuries you can play with, but I actually don’t think you can do that with Robin’s injury.”