CHICAGO - The Twins clubhouse was abuzz late Tuesday night, and the team's career saves leader was worked up.

Joe Nathan had 30 minutes to decide if he was open to a trade.

The Twins insisted they didn't have a deal cooking. They were just checking to see if Nathan wanted to move to a contender, as they did last week with Jim Thome.

Nathan has 10-and-5 rights -- 10 years of major league service, five with the same team -- which gives him veto power over any trade.

A player must sign a consent form to waive his 10-and-5 rights at least 24 hours before he's traded, and that decision had to be made before Tuesday at 11 p.m., since Wednesday night was the deadline for teams to submit potential postseason rosters.

"The tough part was the timing," Nathan said. "They came to me with 30 minutes left until the deadline."

Nathan declined to sign the consent form, basically ensuring that he'll finish the season with the Twins. His contract includes a team option for $12.5 million next year with a $2 million buyout.

Nathan said if he didn't have the option year, he probably would have waived the 10-and-5 rights, since it would have been a shorter-term decision. He and his agent, David Pepe, discussed trade scenarios where they could possibly use the 10-and-5 leverage to get his next team to pick up the option.

By signing that consent form, he would have been waiving that right.

"It seemed the smart decision for us to say we're not going to waive [the 10-and-5 rights]," Nathan said. "It's nice to be here and have a chance to possibly be with this club again next year. We'll see what that brings."

At this point, it seems unlikely the Twins would pick up Nathan's option, but it's possible the sides will sit down and work out a new deal this fall.

Nathan turns 37 in November. He is 17 months removed from Tommy John surgery and has regained much of his pre-surgery form.

It's tough to know for sure because the Twins have given him so few save chances. Wednesday brought the first one in two weeks. Nathan entered in the ninth inning with a 7-4 lead, and the White Sox trimmed it to 7-6 before he struck out Alex Rios with an 88-miles-per-hour slider to end the game.

Earlier, Nathan threw four consecutive 95-mph fastballs when he struck out Adam Dunn. His pitches have late life again, which has helped him convert nine consecutive save chances and post a 2.11 ERA in his past 22 appearances, with 19 strikeouts and four walks in 21 1/3 innings.

At some point in August, Nathan cleared waivers. It's possible the Twins pushed him through early in the month, when he was still trying to find his groove. Any team that claimed him would have risked being on the hook for his remaining salary this year -- about $2 million as of Wednesday -- and the $12.5 million option or $2 million buyout for next year.

The Twins probably wouldn't have been able to get much for Nathan in a trade unless they were willing to eat some of his salary.

The Giants, who are dealing with Brian Wilson's elbow injury, claimed Padres closer Heath Bell, but the sides didn't work out a deal. Other potential fits for Nathan would have been the deep-pocketed Yankees, Red Sox or Phillies.

If Nathan had gone to a contender, he would've had to test himself again in high-pressure situations, and one way or another, that would've impacted his potential free-agent value.

The Twins won't have as much at stake this month, but if Nathan continues to post good numbers, he'll be in position for another big contract, even if it prices him out of Minnesota.

Joe Christensen jchristensen@startribune.com