Chelsea defender Gary Cahill believes the busy fixture schedule is taking its toll on him and his team-mates as the club compete on three fronts this season.
Alongside their push for a top-four Premier League finish, Rafael Benitez's men are also competing in the FA Cup and UEFA Europa League.
After next week's international break, Chelsea will take in a run of six games in 16 days, including a two-legged Europa League quarter-final and the replay of their FA Cup last-eight tie with Manchester United.
While reluctant to make excuses for the Blues' inconsistent form this season, 27-year-old centre-half Cahill admits the congested fixture list is proving tough.
He told the Daily Telegraph: "People criticise you if you say you are tired, and we know we have to get on with it because the fixtures are there.
"But all I am saying, as a general fact, is that players do not go into every game feeling 100 per cent fresh, it is impossible.
"At a big club every single game is so important, but you might be going in 60-70 per cent fresh through no fault of your own.
"Everyone is trying to recover but you just don't have the days. It is not an excuse, but it is a fact."
Competition
Cahill, who joined Chelsea from Bolton in January 2012, has notched up 38 appearances for the club in all competitions so far this season and has missed just one Premier League game this year.
Despite cementing his place as a first-team regular under Benitez, the England international is taking nothing for granted with the likes of John Terry and David Luiz also competing for the centre-half berth.
He said: "The main thing is that I am playing in a lot of the big games, I am playing more regularly now, but we have got the luxury of four centre-backs now so we can chop and change.
"I think maybe I proved when I first came that I could play in the Champions League, because we went on and won it, and I played the games in there. Playing with England has helped me as well.
"You come here from a smaller club and people wonder, can he play here, can he do this? And you always feel like you are trying to prove yourself to people all the time. For me now it is just trying to prove that I can maintain a starting place at Chelsea."
Fellaini was booed off by fans when he was replaced during Everton's shock FA Cup quarter-final defeat last weekend, with supporters unhappy with the Belgian's attitude.
An appearance at an official Everton store earlier this week was postponed and Moyes accepts Fellaini's stock may have fallen with the fans.
However, Moyes is prepared to give the 25-year-old a chance to make amends when Everton face Premier League champions Manchester City at Goodison Park on Saturday.
"His reaction wasn't right, it wasn't the correct one and I have told him that," said the Everton manager.
"He knows that he should have played much better, and yes, he may have some making up to do with the fans, but I won't have any trouble picking him.
"I'll play Marouane against Man City as I have to give us the best chance of winning. That means picking our best players and giving them a chance to make amends.
"Don't forget the good stuff he's done. For the most part he's been outstanding and made a huge contribution.
"Most of the lads had a disappointing day, even if he found it tougher than most.
"He may not be firing as he might, but he's still been influential for us. He is the only player I'm talking about, but there were eight others we could be talking about."
