Nathan Cleverly will continue his light-heavyweight comeback against Andrzej Fonfara, having decided not to face WBA champion Juergen Braehmer.
Cleverly said in May that the Braehmer fight was "provisionally agreed".
"The Juergen Braehmer fight was one we were very close to taking," Cleverly's promoter, Eddie Hearn, confirmed.
"But we just felt that after his big win against Julio Cesar Chavez Jr, Fonfara was the perfect fight on the world stage."
Braehmer's promoters, Team Sauerland, confirmed on Twitter that Cleverly "turned down the world title fight against Braehmer".
The German was due to fight Cleverly in 2011 only to withdraw injured, which saw the Welshman inherit his WBO title, but it seemed that the two would finally face each other next September.
Cleverly is instead now set to face Polish fighter Fonfara. The exact date and venue have yet to be announced but the fight has been pencilled in for October 2015.
Fonfara, 27, has a 27-3 record with 16 knock-outs, and the Chicago-based boxer's last fight was a nine-round stoppage of former middleweight world champion Chavez Jr.
Welshman Cleverly, 28, has a 29-2 record with 15 knock-outs and while WBO champion defended his belt five times with wins over Aleksy Kuziemski, Bellew, Tommy Karpency, Shawn Hawk and Robert Krasniqi.
Cleverly lost to Tony Bellew at cruiserweight in November 2014 but made his comeback at light-heavyweight with a 24-second stoppage of Czech journeyman Tomas Man last May.
"We have had lots of big fight offers come in from Nathan over the past few months and we have taken our time to choose the right one," Hearn added.