He was set to make his return to the UFC against Thiago Silva but unfortunately, Silva suffered an injury and pulled out a week and a half before the fight. UFC newcomer Todd Brown stepped in as his replacement. Boetsch defeated Brown via a relatively lackluster unanimous decision.
He next faced undefeated wrestling wrecking machine Phil Davis. He lost by kimura. He next dropped to middleweight, debuting against TUF winner Kendall Grove. Boetsch looked excellent at one hundred and eighty-five pounds, defeating Grove via a dominant unanimous decision.
He next faced officially TUF veteran Nick Ring, winning via unanimous decision.
Boetsch next signed up for a big step up in competition in perhaps the biggest fight of his career against former title contender Yushin Okami in Okami's native Japan. After being dominated for two rounds, Boetsch listened to his corner and came out looking for a finish at the start of the third and final round. The result was a memorable and devastating comeback knockout. Boetsch stepped into the top ten rankings in the UFC middleweight division.
Boetsch was next set to face TUF winner Michael Bisping but Bisping was injured. Boetsch instead stepped in to replace an injured Brian Stann against UFC newcomer and former Bellator middleweight champion Hector Lombard. Boetsch defeated Lombard via a controversial and disappointing split decision.
Boetsch was next set to face undefeated contender Chris Weidman in December 2012 before Weidman was injured and replaced by Constantinos Philippou. Boetsch lost via third round technical knockout to Philippou.
After a decent layoff, Boetsch signed in March 2013 to fight Mark Munoz on Fourth of July weekend 2013. Fireworks certainly went off that night as Munoz defeated Boetsch via an exciting unanimous decision.
Boetsch wasted little time in next signing to fight the talented former Strikeforce middleweight champion Luke Rockhold. Rockhold was unfortunately injured in September 2013 and replaced by C.B. Dollaway. Boetsch defeated Dollaway via an extremely controversial split decision in a fight that Dollaway looked spectacularly improved in.
Boetsch next signed again in February 2014 to fight Rockhold. Rockhold won via a first round kimura submission.
Boetsch next fought Brad Tavares defeating Tavares via a second round comeback knockout.
Boetsch then fought contender Thales Leites hurting Leites early but eventually losing via second round technical arm triangle submission.
Boetsch then fought future UFC Hall of Famer, former Strikeforce light-heavyweight champion and two-time Pride champion Dan Henderson in Boetsch's first UFC main event. Henderson knocked out Boetsch in just twenty-eight seconds.
Boetsch next moved up briefly back to light-heavyweight to fight fellow former middleweight Ed Herman. After a sloppy back-and-forth fight Herman defeated Boetsch via second round TKO.
Boetsch then fought former Strikeforce middleweight champion and UFC middleweight contender Ronaldo Souza. Souza defeated Boetsch via a first round kimura submission.
Boetsch next signed to fight former UFC welterweight champion Johny Hendricks.
- Tim Boetsch vs. David Heath - The fight was Boetsch's UFC debut, replacing injured Tomasz Drwal on short notice, only ten days' notice.
- Matt Hamill vs. Tim Boetsch - Tim Boetsch came into the fight on ten days notice to replace an injured Stephan Bonnar.
- Tim Boetsch vs. Mike Patt - The fight was the UFC debut of Mike Patt.
- Jason Brilz vs. Tim Boetsch - After the fight, Boetsch was cut.
- Phil Davis vs. Tim Boetsch - After the fight, Tim Boetsch moved down to middleweight.
- Tim Boetsch vs. Kendall Grove - The fight was Boetsch's middleweight debut. Kendall Grove was cut afterwards.
- Tim Boetsch vs. Nick Ring - The fight was the first loss for Nick Ring.
- Tim Boetsch vs. Yushin Okami
- Tim Boetsch vs. Hector Lombard - The fight was the long-awaited UFC debut of former Bellator middleweight champion Hector Lombard. The fight's decision victory result for Boetsch was considered to be extremely controversial.
- Mark Munoz vs. Tim Boetsch
- C.B. Dollaway vs. Tim Boetsch -C.B. Dollaway was a late replacement for an injured Luke Rockhold.
- Thales Leites vs. Tim Boetsch
- Dan Henderson vs. Tim Boetsch
- Ed Herman vs. Tim Boetsch - The fight was Boetsch's return to 205 pounds.
- Tim Boetsch vs. Josh Samman - The fight was Boetsch's return to middleweight.