Sir Alex Ferguson has labelled his five-game touchline ban “disappointing”, but the Manchester United manager has decided not to appeal.

Ferguson was found guilty of improper conduct by the Football Association for criticising referee Martin Atkinson after the 2-1 loss at Chelsea earlier this month.

“It is disappointing,” he said. “It is the only industry where you can’t tell the truth. But it is in the past now.”

The FA announced yesterday evening that Ferguson will not appeal his five-match ban.

“The FA can confirm that Manchester United will not be appealing Sir Alex Ferguson’s five-game touchline ban,” the FA statement said. “Manchester United have also requested that the ban starts with immediate effect. This has been accepted by the FA.”

To add to Ferguson’s woes, he revealed his fears that defender Rio Ferdinand could miss the remainder of the season due to an on-going calf problem.

The England centre-back has not played since suffering the problem in the warm-up prior to the club’s first Premier League defeat of the season at Wolves in early February.

Ferguson said: “Rio has been out for a few weeks now. We are not looking at this as a short-term situation.

“He has not started training yet. We will be lucky to get him back for some part of the season. It’s a big blow but sometimes calf problems can be troublesome.

“I remember Bryan Robson in 1990. He was out for four months with a calf injury. It’s looking that way again with Rio.”