Glen Johnson will meet Allan Green

Former light heavyweight champion Glen Johnson is joining the Super Six World Boxing Classic, replacing injured Mikkel Kessler, Showtime announced Wednesday.

Johnson, 41, has not fought at super middleweight since 2000, but will drop down to the 168-pound weight class to face Allan Green in a Group Stage 3 bout on Nov. 6. The fight will take place at the MGM Grand in Las Vegas on the undercard of the Juan Manuel Lopez-Rafael Marquez featherweight title fight.

The other two Group Stage 3 bouts are scheduled for a Nov. 27 split-site doubleheader with Andre Ward defending his belt against 2004 U.S. Olympic teammate Andre Dirrell at an American site to be determined and Carl Froch facing Arthur Abraham in Helsinki, Finland.

Ward has already secured a spot in the semifinals of Showtime's six-man modified round-robin tournament, but the five other fighters all remain alive based on the way points are earned -- three for a knockout win, two for a win and one for a draw.

Johnson (50-14-2, 34 KOs) will enter with no points and Green (29-2, 20 KOs), himself a replacement for Jermain Taylor, who dropped out after Group Stage 1, also has no points. However, the Johnson-Green winner can advance only with help from results in the other two bouts.

Kessler, who was supposed to fight Green, dropped out in late August because of an eye injury. He exits the tournament 1-1 with two points.

Ward, who is 2-0 in the tournament, leads the field with four points. Abraham is 1-1 with three points coming from his knockout of Taylor. Froch and Dirrell are each 1-1 with two points apiece. Green lost his only tournament fight via lopsided decision to Ward in Group Stage 2.

Johnson was the 2004 fighter of the year when he knocked out Roy Jones Jr. and then outpointed Antonio Tarver to earn the recognized light heavyweight championship. He is coming off a highly competitive decision loss to light heavyweight titlist Tavoris Cloud on Aug. 7 and was excited to get the opportunity to enter the tournament.

"I want to thank Showtime for including me in their Super Six tournament," Johnson said. "Having dedicated so many years to the sport of boxing, it is gratifying to still be considered worthy of competing with some of the top fighters in the world and on such a prestigious platform."

He said he is not concerned about making the 168-pound weight limit because he has so often weighed in for his 175-pound light heavyweight bouts a few pounds under the limit.

"I typically weigh in at 172 pounds for my light heavyweight fights," he said. "I will have no trouble making the 168-pound limit as a super middleweight."

When the possibility of getting the spot in the tournament came up a few days ago, Johnson said he was going to start working on his weight immediately, even before his entrance was official.

The Miami, Fla., resident has been working out with Lucian Bute, who has a super middleweight title was not invited to join the tournament when it was put together in July 2009. Bute was not a candidate to replace Kessler as he is already signed to make a mandatory defense against Jesse Brinkley on Oct. 15 in Montreal.

Dan Rafael is the boxing writer for ESPN.com; follow him on Twitter @danrafaelespn.