FORT MYERS, Fla. -- The Twins and closer Joe Nathan appear to be in the final stages of reaching the terms of a contract extension that could be announced as soon as Monday.

Nathan's agent, Dave Pepe, was in the Orlando area visiting other clients on Sunday, but he was scheduled to arrive back in Fort Myers and meet with the Twins on Monday morning to go over some final details, said a source with knowledge of the discussions.

Indications are that it would be a four-year deal. The exact amount is not known, although ESPN's Buster Olney has reported that the contract would pay Nathan between $11 and $12 million a year.

That would put Nathan's contract in the same price range as closer Francisco Cordero, who signed a four-year, $46 million contract with the Reds that includes a fifth-year option this offseason. The contracts for Cordero and Mariano Rivera, who re-signed with the Yankees this offseason for three years and $45 million, were credited with setting a new bar on the market for closers.

The Twins first approached Nathan, who is set to make $6 million in 2008, about a contract extension early last month. The two sides went through a brief stalemate period before talks heated up again recently.

Nathan, 33, has posted a 1.00 ERA in nine innings so far this spring, and he has held opponents to a .167 batting average against. He has recorded 160 saves since becoming the Twins' closer in 2004.