The Twins declined Nathan's $12.5 million club option for 2012 on Oct. 25, instead deciding to exercise a $2 million buyout. They remained interested in bringing Nathan back, but he opted to sign with the Rangers.
Nathan, who turns 37 on Tuesday, is scheduled to be introduced by Texas during a news conference at Rangers Ballpark in Arlington at 9 a.m. CT the same day.
Nathan posted a 4.84 ERA with 13 saves in 48 appearances over 44 2/3 innings in 2011. He pitched much better after a stint on the disabled list that began in late May after experiencing a setback related to the Tommy John surgery that kept him out of action in 2010.
After returning from the DL on June 25, Nathan had a 3.38 ERA with 28 strikeouts and 11 walks in 31 appearances over 29 1/3 innings while converting 11 of 12 save opportunities.
The 11-year veteran (seven in Minnesota) holds the Twins' record for saves, with 260. He picked up No. 255 on Aug. 10 to become the all-time leader, passing Rick Aguilera, who set the previous record, with 254 saves from 1989 to 1998.
Nathan was acquired by the Twins in 2003 -- along with pitchers Francisco Liriano and Boof Bonser -- in a trade that sent catcher A.J. Pierzynski to the Giants. In his seven years with the Twins, Nathan posted a 2.16 ERA and was named to four All-Star teams.
Nathan indicated at the end of the 2011 season that his preference was to sign with a winning team, and the Rangers certainly fit the bill, having represented the American League in the last two World Series.
"If a club is interested in me and is interested in signing me back, they have to have the intention that the team is going to win and they are going to put a team out there that is going to be competitive," Nathan said on the final day of the season. "I feel like I'm in kind of a good position with that."
With Nathan headed to the Rangers, the Twins could be looking for a closer through free agency or trade. They remain interested in re-signing Matt Capps, who lost his job as closer to Nathan in mid-July and is currently a free agent.
The Twins could also turn to left-hander Glen Perkins -- who excelled with a 2.48 ERA in 2011 -- to be the closer next season, but he has just two career saves and could remain in a setup role.