Shane Carwin

In late 2017, Carwin was in negotiations with Bellator MMA but nothing came to fruition, despite his injuries being rehabilitated.

On July 26, 2016, Carwin announced his plans to return to MMA, five years since his last competitive bout. On September 7, 2016, Carwin announced that he had worked with his management team at Ingrained Media to secure his release from the UFC and became a free agent. On October 28, 2016, Carwin announced he had signed with Rizin Fighting Federation. He stated that he expected to debut on their December 29, 2016, card, but later withdrew with injury.

On October 15, 2016, Carwin participated in a boxing exhibition match against professional skateboarder Jason Ellis at EllisMania 13. Per the unique rules, Carwin had one of his arms duct-taped to his body to box Ellis. He won the bout via knockout in the second round.

On May 7, 2013, Carwin announced his retirement from mixed martial arts (MMA) after enduring several injuries since his last fight on June 11, 2011.

On Thursday July 12, 2012, Dana White announced that Carwin and Roy Nelson had been picked as the next coaches for the 16th season of The Ultimate Fighter (TUF) and were expected to face each other on December 15, 2012, at The Ultimate Fighter: Team Carwin vs. Team Nelson Finale. However, on November 14, 2012, Dana White revealed on Twitter that Carwin injured his knee and would not be facing Nelson in the TUF finale.

Carwin was scheduled to face former IFL Heavyweight Champion Roy Nelson on January 1, 2011, at UFC 125; however, he later announced on his website that he would pull out of the fight due to back and neck pain, which required surgery that took place on November 2, 2010. Carwin later stated that the neck surgery was a success. On January 3, 2011, Carwin posted a blog entry on his website, stating that he had just begun his first day of training since his neck surgery, hoping to be back in the octagon by May or June 2011.

Carwin was expected to face promotional newcomer Jon Olav Einemo on June 11, 2011, at UFC 131. However, another bout with diverticulitis sidelined Brock Lesnar, so Carwin agreed to step in to the main event to fight Junior dos Santos. Carwin was defeated by Dos Santos via unanimous decision (30–27, 30–27, and 30–26). This fight was the first in Carwin's career to ever go to a decision.

On September 9, 2011, Carwin posted a blog entry on his website stating that he was 100% healthy and looking to return to the octagon in late December or early January. On October 16, 2011, it was revealed that Carwin would need back surgery. He was expected to be out until mid-2012. However, his recovery took longer than expected, and he was targeting a return to fighting that fall.

Carwin fought former UFC Heavyweight Champion Frank Mir for the UFC Interim Heavyweight Championship on March 27, 2010, at UFC 111. Carwin stated on his website that, "Mir is a legend of the sport, and I would be honored to fight him." Early in the first round, Carwin dropped Mir with multiple uppercuts from the clinch. Carwin then followed Mir to the ground, took back mount and rained down heavy punches on Mir's head thus winning the fight via knockout to become the UFC Interim Heavyweight Champion. The bout also marked the longest fight of Carwin's career at three minutes and 48 seconds; his previous mark was his MMA debut against Carlton Jones, with a time of 2 minutes and 11 seconds. Following UFC 111, Beau Dure of USA Today compared Carwin to Mike Tyson, echoing a similar comparison made prior to the event by Mark Wayne of Fightline.com.

Carwin is divorced and has a son from a previous marriage. He has a daughter named Alexia, born on February 24, 2010.

Carwin was then set to face fellow undefeated heavyweight contender Cain Velasquez at UFC 104, with the winner getting a title shot against then-champion Brock Lesnar; however, the UFC reconsidered the bout and Carwin was confirmed to fight for the title at UFC 106 on November 21, 2009. The fight was later postponed after Lesnar pulled out due to illness, with UFC 108 a likely date. Lesnar then pulled out of that fight on October 26, and Dana White reported at the UFC 105 post-fight press conference that Lesnar was too ill to compete and was expected to be out for the first half of 2010 while recovering from an intestinal disorder and subsequent surgery.

Carwin wrestled in college, becoming a two-time NCAA Division II Wrestling National Runner-Up as a heavyweight in 1996–97 and the NCAA II Wrestling Heavyweight National Champion in 1999. He was also a two-time All-American in football for Western State and was chosen to participate in the Senior Bowl. Carwin is also a volunteer wrestling coach for the University of Northern Colorado.

Shane Bannister Carwin (born January 4, 1975) is an American former mixed martial artist who competed in the Heavyweight division of the Ultimate Fighting Championship (UFC). He is a former Interim UFC Heavyweight Champion.