LAS VEGAS, Nevada :Glen Johnson, a former world light heavyweight champion, drops down to fight American Allan Green on Saturday to contest a semi-final berth in the Super Six super-middleweight tournament.
Both fighters are injury replacements in the six-man event, in which World Boxing Council (WBC) and World Boxing Association (WBA) crowns are on the line.
The group stages conclude this month, with semi-final and title bouts scheduled for next year.
Jamaican-born Johnson, 50-14 with two draws and 34 knockouts, has not fought at super-middleweight in 10 years but at the age of 41 he is seeking a title chance by filling in for Danish fighter Mikkel Kessler, who had an eye injury.
Green, 29-2 with 20 knockouts, replaced injured countryman Jermain Taylor in the field. He lost a unanimous decision to unbeaten US fighter Andre Ward, 22-0 with 13 knockouts, in June on his Super Six debut.
WBA champion Ward is set for the semi-finals and Germany`s Arthur Abraham and Britain`s Carl Froch will both advance no matter the result of their WBC title fight on November 27 in Helsinki.
Ward had been set to fight American Andre Dirrell, another replacement fighter, in a title defence but Dirrell dropped out last month with neurological problems.
Instead, Ward will step outside the tournament to risk his title on November 27 in his hometown of Oakland, California, against Cameroon-born Australian fighter Sakio Bika, 28-4 with two draws and 19 knockouts.
The Green-Johnson fight will be staged on the undercard of undefeated Puerto Rican southpaw Juan Manuel Lopez`s fight with Mexico`s Rafael Marquez for Lopez`s World Boxing Organization (WBO) featherweight crown.