Hernandez, formerly known as Fausto Carmona prior to the discovery that his identity had been falsified, signed a one-year deal worth $3.25 million; an additional $1.85 million can be earned in incentives.
Hernandez can be used in the bullpen or in the starting rotation. He's known for being a ground-ball specialist due to a "heavy" sinker.
"Right now we're confident that he's going to help us get meaningful outs and will continue to allow our pitching to be a strength," said Rays executive vice president of baseball operations Andrew Friedman. "We're not sure exactly what role we'll use him in, but obviously he's got a lot more experience starting than pitching out of the bullpen.
"We feel like there's a lot of upside with him and that with his ground-ball tendencies, he'll fit in extremely well with our infield defense and what we're envisioning it to be in 2013."
Losing James Shields in a recent trade with the Royals has put the Rays in a situation where they will have to make up for a lot of innings previously accounted for by the workhorse, who pitched 200-plus innings six straight seasons. Hernandez looks made to order for what Tampa Bay needs.
"This guy's got experience logging a lot of innings in the rotation," Friedman said. "He's gotten up to 215 and has thrown over 200 a couple of times, a couple of times gotten close to 200. And whether he's in the rotation or not, making our bullpen deeper to account for the lost innings is something that's very much on our mind."
Hernandez, 32, finished fourth in American League Cy Young Award voting in 2007 -- posting a 19-8 record with a 3.06 ERA, and he was an All-Star in '10. Cleveland did not exercise a $6 million club option to retain him for the '13 season.
Hernandez was arrested on Jan. 19 in the Dominican Republic for using the false name Fausto Carmona, when his real name was reported to be Roberto Hernandez Heredia. He was arrested while leaving the American consulate in Santo Domingo, where he had gone to renew his visa so he could return to the United States for Spring Training.
Hernandez's birth date had been listed as Dec. 7, 1983, which would have made him 17 years old when he signed with the Indians as a non-drafted free agent in 2000. His birth date is now listed as Aug. 30, 1980.
In 2012, Hernandez made only three starts, all in August, and went 0-3 with a 7.53 ERA. He began the season on Major League Baseball's Restricted List due to visa issues stemming from his arrest. After returning to the United States, Hernandez served a three-week suspension imposed by Major League Baseball and was then activated. A sprained right ankle sustained on Aug. 27 ended his season.
"This guy's got really good stuff," Friedman said. "The two-seamer -- which he gets a lot of ground balls with -- the slider, the changeup; we feel like he's got the repertoire to get out right-handed and left-handed hitters.
"Obviously last year was a lost year for him in a lot of respects. But we feel like this is one of those risk-reward stories that make a lot of sense for us, and the upside is really compelling and gives us a chance to add to our pitching depth, which is something that is a focus for us in a way that it hasn't been in previous years."
Hernandez has compiled a 53-69 record and a 4.64 ERA over 184 games (153 starts), and he has limited right-handed hitters to a .243 batting average over his career.
Already this offseason, the Rays have added first baseman James Loney, shortstop Yunel Escobar and handful of Major League-ready prospects from the Royals in addition to Hernandez. Though a lot of Tampa Bay's work has been done, Friedman said he would like to add "one or two more relievers" and "a bat or two" before camp opens in Port Charlotte, Fla., in early February.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.