Cologne left-back Jonas Hector's agent has told kicker that the Germany international, reportedly a target for Liverpool, has been permitted to negotiate with other clubs.
"We've discussed our course of action with the Cologne hierarchy before the winter break," Hector's agent Rainer Derber told kicker.
"FC already reacted to Jonas' potential transfer with the signing of Mladenovic. Upon consultation with FC Cologne we are allowed to talk to interested clubs. But this won't happen before the Bundesliga final."
Hector in the past has been linked with Liverpool, where he could become Jurgen Klopp's second Bundesliga signing in the upcoming transfer period. According to local paper Kolner Stadtanzeiger, Wolfsburg are also said to be interested in the Germany international.
Derber said: "Jonas knows what it's like to sign a contract. Not only he would have to profit from a transfer but also the FC."
Since his debut in November 2014, Hector has been a permanent fixture in Germany's starting formation, winning 12 caps, and the only national team player to start in all nine matches in 2015.
In March 2016, Hector registered his first goal for die Nationalmannschaft in a 4-1 win against Italy.
Hector has been a mainstay for 1.FC Cologne, who secured another year of top flight football with a 4-1 win against SV Darmstadt at the weekend.
Since Cologne's return to the top flight in 2014, he has played 5649 of a possible 5850 Bundesliga minutes.
He also proven his versatility after he was moved into a holding midfield role by coach Peter Stoger earlier this year, with winter signing Filip Mladenovic taking Hector's position at left-back.