Sunderland captain Lee Cattermole believes that tiredness is at fault for the Black Cats lacklustre end to the season.
The North East side finished 13th in the Premier League this season, with critics claiming that Martin O'Neill's side lost motivation.
"I honestly don't think we took our foot off the gas or anything like that, which people do think. You want to win every game," Cattermole told the Sunderland Echo.
"But we had such a big effort to pull ourselves out of the position we were in. If you look at the players who have played, it's only been the same 13 or 14 lads.
"There's a lot of tired players in there, especially after the FA Cup with the replays against Middlesbrough and Everton. It does take its toll, not only physically, but mentally. Overall, I think we've done brilliant since the turn of the year."
Sunderland lost three of their last eight games in the league.