After being unsigned last season until May, Fister is now the first free agent to finalize a big league contract and the first to switch teams.
"The Rangers approached me with a quality offer, and I figured it was definitely a fair one, and I think that was something we both can benefit from," Fister said. "That's kind of why I went ahead and went with it."
Asked if his experience last season made him want to move a bit more quickly this offseason, Fister responded, "I'm sure that it had something to play into all of this."
Fister moves into a Rangers rotation that had only left-handers Cole Hamels and Martin Perez signed for next season. Fister will get a $3.5 million base salary for 2018, and the contract has a $4.5 million team option for 2019 that includes a $500,000 buyout.
The 33-year-old right-hander agreed last May to a minor league deal with the Los Angeles Angels. He made three Triple-A starts before he requested his release and was claimed off waivers by Boston.
Fister made his debut with the Red Sox on June 25, and he went 5-9 with a 4.88 ERA while starting 15 of his 18 games. He had a seven-start stretch from July 1 to Sept. 6 when he went 5-2 with a 2.79 ERA and held opponents to a .194 batting average.
"I really feel like I've reverted back to some of my old ways, of pitching philosophy and physical mechanics," said Fister, who also got his sinker back.
In 230 games over the past nine major league seasons with five different teams, Fister is 82-85 with a 3.68 ERA. His best season was with Washington in 2014, when he was 16-6 with a 2.41 ERA in 25 starts.
After going 5-7 for the Nationals in 2015, he went to Houston as a free agent and was 12-13 with a 4.64 ERA in 32 starts before his extended free agency.
"Doug profiles the kind of guy we were looking for, excellent makeup, pounds the strike zone, success in the American League," general manager Jon Daniels said. "Without elite velocity, he has got excellent command and excellent movement."
Daniels said the Rangers are still in the market for starting pitching and bullpen help. Texas is among the teams interested in Shohei Ohtani, the star pitcher-hitter from Japan.
Fister said he was able last season to make changes that allowed him to repeat his delivery and get his pitch quality back where it used to be. He also looks forward to being able to prepare for and go to spring training.
"Having that natural timeline of getting into the season I feel like is going to be a benefit for me," Fister said. "I feel 100 percent healthy and being able to get back and manipulate the baseball the way I used to."