Atletico Madrid midfielder Koke would welcome the return of Filipe Luis from Chelsea if the two teams can agree terms, and rejected suggestions the defender is a "traitor" for leaving the Calderon.
Filipe Luis, 29, left the Rojiblancos from Stamford Bridge in a £15.8 million transfer just 12 months ago.
The Brazil international is under contract with Chelsea until June 2017 but Atletico are keen to have their former left-back in the squad again.
Atletico president Enrique Cerezo told Spanish radio station Cadena Cope: "There are negotiations in place but I don't know how fruitful they will be.
"Filipe Luis is a magnificent player. We would be delighted if he comes back and I think that in the end, we can find a solution.
"The financial aspect always takes precedence over the sentimental aspect but I believe a solution can be found."
Atletico cannot afford to pay Filipe Luis' high wages and the player may have to consider a pay cut to move back to Spain.
A section of the Spanish club's fans labelled him "a mercenary" following his departure after four years at Atletico.
The defender had said at the time that he was worried about being "too comfortable at Atletico," and that he wanted to finish his career elsewhere in a "strong and spectacular way."
Koke said as reported in Spanish sports newspaper Marca: "Filipe is not a traitor. Filipe decided to leave and now he has the possibility to return.
"If he does come, there will be more competition in the team and that is good. We will be a better side and we will fight to achieve more aims.
"As long as he plays and does well, there will be no problems."
Filipe Luis made 127 appearances for Atletico in his four years with the team, helping Diego Simeone's side win the 2012 UEFA Cup, 2013 Copa del Rey and La Liga in 2013-14.
He made 26 appearances for Chelsea in all competitions last season, including just nine league starts for the Premier League champions.
Cerezo said on Thursday that Atletico will continue to strengthen their squad for the 2015-16 campaign by adding two more players next week.
Atletico have sold Belgium defender Toby Alderweireld to Tottenham, Croatian forward Mario Mandzukic to Juventus, Brazilian centre-back Joao Miranda to Inter and Turkish midfielder Arda Turan to Barcelona.
They have so far added this summer Argentinian strikers Luciano Vietto and Angel Correa, Belgian midfielder Yannick Carrasco and Colombian forward Jackson Martinez.
Atletico finished third in La Liga behind Real Madrid and champions Barcelona, and will play in next season's Champions League.