Isami Kodaka
On January 17, 2014, DDT announced that the promotion and Sato had decided not to renew their contract with each other. Sato wrestled his final match under his old DDT contract on January 26, when he and Sanshiro Takagi defeated Akito and Yukio Sakaguchi in a tag team match. Afterwards, Sato began working for DDT's sub-promotion Union Pro Wrestling, while also producing occasional Hard Hit events for the promotion. Sato also continued working for AJPW, where, on February 16, Suwama accepted Sato's direct appeal and allowed him to join himself and Joe Doering, turning their tag team named Evolution into a stable. After starting a storyline, where he began disrespecting Union Pro, Sato won the promotion's top title, the Union Max Championship, by defeating Isami Kodaka on May 18. He made his first successful title defense on June 19 against Hiroshi Fukuda. On July 7, Sato and Masaaki Mochizuki defeated Hub and Mazada, and Dr. Wagner Jr. and Nosawa Rongai in a three-way elimination match to win Tokyo Gurentai's Tokyo Intercontinental Tag Team Championship. On July 27, Sato received another shot at AJPW's World Junior Heavyweight Championship, but was defeated by the defending champion, Atsushi Aoki, who afterwards agreed to join Sato in Evolution. On August 31, Sato made his second successful defense of the Union Max Championship by wrestling Shuji Ishikawa to a thirty-minute time limit draw. His third successful defense took place on September 15, when he defeated Daichi Kazato. On October 22, Sato and Atsushi Aoki won the 2014 Jr. Tag Battle of Glory, defeating Último Dragón and Yoshinobu Kanemaru in the finals. Directly following their win, Sato and Aoki agreed to a World Junior Heavyweight Championship match to determine the top junior heavyweight in the company. The match took place on October 29 and saw Aoki defeat Sato to retain his title. As a result of winning the Jr. Tag Battle of Glory, Sato and Aoki earned a spot in the year-end World's Strongest Tag Determination League, where, as the only junior heavyweight team, they finished with a record of two wins, one draw and four losses. On December 17, Sato lost the Union Max Championship to Fuma in his third title defense. On March 14, 2015, Sato received his first non-junior title shot in AJPW, when he unsuccessfully challenged Kenso for the Gaora TV Championship.