No he is not he will be facing triple H at summerslam 2012.
Brock Lesnar will be fighting Triple H next at SummerSlam after The Game fired him a few months back. On the latest edition on Raw, Brock took out his anger on Shawn Michaels and broke his arm.*As of August 17th, 2012
The cast of Summerslam - 2012 includes: Bryan Danielson as Daniel Bryan Steve Dez as Entertainer Chris Jericho as Chris Jercho Brock Lesnar as himself Paul Levesque as Triple H Nick Nemeth as Dolph Ziggler
No. Brock Lesnar retired from the UFC at the end of 2011. He returned to the WWE in April 2012 and started a feud with John Cena which culminated in a match between the two at the Extreme Rules pay-per-view. After that Lesnar stated a feud with Triple H and defeated him in a match at Summerslam 2012. A Rematch between the two also happened at the Wrestlemania 2013 pay per view. It is also said that Lesnar has renewed his contract with WWE and hence will continue to be with them for the next few more years.
No. Brock Lesnar kayfabe resigned. He is still with the WWE company.
The year 2012 was very strong for the WWE in terms of returning superstars. The following wrestlers returned to the WWE: a. Underaker b. Triple H c. Brock Lesnar d. Chris Jericho and e. Tensai Tensai returned as a full time wrestler and is still with the WWE. Lesnar returned on a part time basis and has wrestled 3 times since he returned. Undertaker has fought only at Wrestlemania in both 2012 and 2013. Triple H fought at wrestlemania last year and this year plus had a match with Brock Lesnar at summerslam 2012. Jericho returned almost full time, took a short break and then came back.
The Undertakers 21st opponent has yet to be named. It has been rumoured that his opponent will be revealed at SummerSlam 2012 or around that time, before or after. The main rumour for the Undertakers 21st opponent is Brock Lesnar.
Goldberg has beaten Brock. Kurt Angle has also beaten Brock in the WWE.John Cena has beaten Brock at Extreme Rules 2012.
Cena
Brock Lesnar was never retired. In 2004 Lesnar departed from World Wrestling Entertainment (WWE) to pursue a career in the National Football League (NFL). After the NFL, Lesnar pursued a career in mixed martial arts. In 2008, reached a deal to fight with Ultimate Fighting Championship (UFC). In 2012, Lesnar returned to the WWE. In March of 2015, Brock Lesnar announced on ESPN that he signed a new contract with WWE.
John Cena won this match
brock lesnar made a return to wwe because he went to U.F.C got a heart condition and had to retire so he made his way back to the wwe and targeted john cena