General manager Terry Ryan said on Tuesday the Twins are "probably going to be looking outside" the organization to fill their closer role, as left-hander Glen Perkins is expected to remain in his current role as the club's top setup man.
"We're going to look via free agency or through trade," Ryan said. "There are quite a few good closers out there."
Nathan, the Twins' all-time saves leader, left Minnesota for Texas on a two-year deal worth $14.5 million that includes an option for 2014. He became a free agent after the Twins declined his $12.5 million club option for the 2012 season on Oct. 25, instead deciding to exercise a $2 million buyout.
Nathan, who turned 37 on Tuesday, cited that playing for a contending team was the biggest factor in his decision to sign with the Rangers. The Rangers represented the American League in the last two World Series, while the Twins finished with the worst record in the American League with 99 losses in 2011.
"It's pretty obvious that I have been able to admire this squad from the other side of the field over the past few years," Nathan said at his introductory press conference in Texas. "This club is a perfect fit for myself and my family. Getting to the postseason and the World Series is huge, and knowing the success that they have had was a huge factor."
Ryan said the Twins had an offer on the table for Nathan, but that he ultimately opted to sign with Texas after eight years in Minnesota, including the 2010 season that was lost to Tommy John surgery. In his time with the Twins, Nathan posted a 2.16 ERA along with a club record 260 saves, while also being named to four All-Star teams.
"He was a part of this organization for a long time, so it's unfortunate that we lost him to the Rangers," Ryan said. "But I understand that Texas is a good organization and Joe felt a comfort there. We're going to miss him. So we're going to have to adjust. We're going to have set our sights on other possibilities."
One possibility could be bringing back free agent Matt Capps, who remains on the club's radar despite posting a 4.25 ERA and losing the closer job to Nathan in mid-July. He battled through injuries throughout the season, and is just one year removed from posting a 2.47 ERA in 2010.
There are also several other free agents with closing experience, including David Aardsma, Jonathan Broxton, Francisco Cordero, Frank Francisco, and Jon Rauch. Ryan Madson, Heath Bell and Francisco Rodriguez are also free agents but are out of the Twins' price range.
The Twins could also turn to a trade, as they had talks with the Nationals before the July non-waiver Trade Deadline regarding closer Drew Storen. And Colorado is also reportedly looking to deal closer Huston Street this offseason.
Either way, the Twins will be adding a new closer, as Ryan indicated that the role will not be filled in from within.
Perkins, who posted a 2.48 ERA with 65 strikeouts in 61 2/3 innings, would have been the top candidate to take over as closer, but the Twins like him in his setup role because he can be used in high-leverage situations anywhere from the sixth to eighth innings.