Aybar, 24, missed all of last season due to an injured right wrist and a stint at a rehabilitation facility for substance abuse. He sustained the wrist injury in Spring Training and underwent surgery in August.
"We really like Willy's offensive profile," said Andrew Friedman, Rays executive vice president of baseball operations. "We feel like he can really hit. We like his defensive versatility. And we plan on expanding that some in Spring Training."
The Rays have not yet said whether top prospect Evan Longoria will be the Opening Day third baseman. Aybar could fill that slot if Longoria isn't in Baltimore when the season begins. But according to Friedman, Aybar primarily adds depth to the roster.
In 105 career Major League games for the Dodgers and the Braves, the switch-hitting Aybar has a .292 average with five home runs, 40 RBIs and a .387 on-base percentage; he has played 81 games at third base and 21 at second. Friedman said the Rays plan to look at him at first and in the outfield as well.
Friedman did not back away from addressing Aybar's problems off the field.
"We did a lot of due diligence into his problems from last year," Friedman said. "While we recognized it's a risk, we feel it's a risk worth taking."
Friedman said Aybar's problem "needs to be monitored."
"And it's something we will be aggressive to help him any way we can to put a support network into place," said Friedman, who noted such issues are a private matter.
Aybar has spent the offseason playing third base for Licey in the Dominican Winter League, batting .268 in 27 regular-season games. He is currently hitting .339 for Licey in the league's round-robin tournament with a home run and six RBIs.
Aybar "has looked great [this winter]," Friedman said. "Which I think is a testament to his natural hitting ability. I think he's cramming in as much as he can this winter to get ready for Spring Training."
Fontaine, 22, opened the 2007 season at Class A Rome and hit .288 with three home runs and 26 RBIs before earning a promotion to Class A Myrtle Beach in August where he hit .205 with no home runs and seven RBIs.
Ridgway, 27, made his Major League debut with the Rays in September after spending seven seasons in the Rays' Minor League system. He made three relief appearances for the Rays and went 0-0 with a 189.00 ERA.
Ridgway went 2-3 with four saves for Durham in 2007, his first full season at the Triple-A level. He led the staff with 54 appearances and struck out 67 in 64 2/3 innings. The South Carolina resident was selected by the Rays in the 14th round of the 1999 June Draft.
"Ridgway is a real good arm," Friedman said. "And he pitched extremely well in '06 and in '07 had some ups and downs, but still pitched very well. ... Everybody who has been associated with him in this organization wishes him the best. Jeff Ridgway has all the tools to be a good Major Leaguer. This is more about Willy Aybar."
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.