Nelson cleared the final hurdle by passing a team physical, which made official his one-year deal worth $1.3 million to join the Rays.
"We feel like Joe can really help our bullpen," said Andrew Friedman, the Rays' executive vice president of baseball operations. "He had a tremendous season in 2008 and has been very effective against both left-handed and right-handed hitters. Our bullpen was a large part of our success in 2008, and our quest is to have one of the top bullpens in the American League on an annual basis. Adding Joe certainly helps on that front."
Nelson sounded happy to be joining his new team.
"I'm ecstatic to be joining the American League champions," Nelson said. "I'm just hoping I don't screw them up and that I'll just be a contributing factor in the bullpen."
Nelson, 34, worked 54 innings with a 2.00 ERA last season but was non-tendered by the Marlins.
"I'll do whatever [Rays manager] Joe [Maddon] wants me to do -- I've talked to him already," Nelson said. "Wherever they need me to throw and in whatever role, I told him I will be completely available and ready for anything."
Nelson could be a critical piece to bolster the team's bullpen for the 2009 season. Maddon has always favored having four pitchers he can hand the ball over to in the late innings with the score tied or with the Rays ahead by one run. Nelson gives the Rays five such pitchers, including right-handers Dan Wheeler, Grant Balfour and Chad Bradford, and left-hander J.P. Howell.
"I have a feeling there's going to be some complementary looks [in the bullpen]," Nelson said. "J.P. throws different than me and I throw different than Grant. Wheeler, he's not as big a strikeout guy as he is a ground-ball guy like Bradford, so I think we're all going to complement each other really well."
Furthermore, Nelson gives the Rays insurance in case closer Troy Percival can't make a successful return from offseason back surgery.
While right-handers hit just .189 against Nelson in 2008, left-handers didn't do much better, hitting .227. In addition, Nelson has shown he can get the big strikeout, as evidenced by his 60 strikeouts in 54 innings last season.
"There are times where you look for the strikeout and times when you'd much rather have a ground ball to the shortstop," Nelson said. "Sometimes you're in a spot where you look for contact, and other times you're put in a spot where you're trying to avoid it."
Nelson was selected in the fourth round of the 1996 First-Year Player Draft and made his big league debut in 2001, but it took him some time to catch on for good. Nelson's first full big league season came in 2006 for the Kansas City Royals, and he spent last season as one of Florida's most consistent relievers.
The veteran didn't pitch for the Marlins in April and made just four appearances in May, but he worked to a 1.69 ERA before the All-Star break and a 2.20 mark after it. Nelson also had a 1.37 ERA in 32 appearances on the road. He also rang up more strikeouts (60) than he allowed hits (42) during his breakthrough season.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.