Sammy Lee has revealed Ivan Campo will be unable to feature for Bolton in the Uefa Cup until February at the earliest.
The Spanish midfielder, who scored in his first appearance of the season against Tottenham on Sunday, was not among the 25 players registered by Bolton to play in Europe.
Campo had fallen out of favour since Lee replaced Sam Allardyce and was given permission to discuss a move away from The Reebok Stadium.
Despite interest from Sheffield United and Qatar Sports Club, the former Real Madrid man decided to stay at Bolton.
The 33-year-old had not been involved in any of Bolton's first seven league and cup games but staked a claim for a regular place with an excellent performance against Spurs.
However, Campo cannot play in the Uefa Cup until after the January transfer window, should The Trotters progress past the group stage, when clubs will be able to make up to three changes to their original lists.
"It would have been remiss of me to have included him in the Uefa squad when he could have gone elsewhere at a moment's notice, with our blessing," Lee told The Bolton News.
"Uefa squads are set in stone once they are named and to have taken up one of the places with a player who might not even have been here, would not have been in the club's best interests."
Meanwhile, striker Kevin Davies is among a number of Bolton's senior players who have met with Lee recently to discuss the club's worrying form at the start of the season.
"We've had a couple of positive meetings," Davies said in the Manchester Evening News. "We just tried to see what everyone can do to help the situation and I think they've really helped.
"The feeling round the place has been bright and two draws (against FK Rabotnicki and Tottenham) are going to give us some sort of confidence to build on."
He added: "There have been so many changes in this club, it's bound to be a difficult transition, but we feel we are turning that corner."