Queens Park Rangers defender Chris Samba has told Sky Sports News that he was not "well prepared" for his return to the Premier League.
Samba, 29, was brought in from Anzhi Makhachkala in January as QPR boss Harry Redknapp looked to move the Loftus Road club clear of relegation trouble.
However, he had not played since November, and Redknapp said after the defender's debut in February that he had then considered himself only "40% fit".
The arrival of Samba - reportedly for a club record £12.5 million - failed to have the desired impact, and QPR's relegation to the Championship was confirmed after Sunday's 0-0 draw with Reading.
Congo international Samba, who took to Twitter to apologise for his performance against Fulham at the start of the month, has now acknowledged that he was unable to make the contribution expected as a result of his fitness levels.
He told Sky Sports News: "From my personal point of view, I don't think I was well prepared to come back to the Premier League. It is the hardest league, and you need to be fully fit and really ready to compete."
He added: "There is a big feeling of failure. Most of us came to help the team, believing we could have an impact."
Samba said he was unsure whether he would still be Loftus Road next season, adding: "I don't know. I am not the only one who makes these decisions. I have failed to help the team, and I only know that I will be much stronger next season."
The defender also played down Redknapp's suggestion that there had been a split at the club.
"I don't know if we can say it is divided. What I can say is that, at every club, there are affinities.
"You go into work and you like to sit with specific people, that is what happens, but if everybody respects each other they can work with each other."