Former Manchester United defender Paul McGrath believes Radamel Falcao is unhappy at Old Trafford.

Falcao was hooked during last night's FA Cup win over Preston.

"Radamel Falcao is not getting the sort of service he would at other clubs he's played for," McGrath told talkSPORT. "United have been a bit nervous and a lot of the team has changed from next season.

"He goes on runs and the ball just doesn't come to him or it comes to him too quickly and it runs through to the goalkeeper.

"He thrives on little things on the box and even those things aren't coming off for him at the moment.

"Maybe it's the pace of English football or the Premier League, but he's out of sorts.

"It's certainly not working out for him. You can see his reaction when he got bought off last night, he's not happy at the club."