Manager Joe Girardi announced the decisions on Saturday before the team's Grapefruit League game against the Pittsburgh Pirates.
Nova figured to be a lock to make the rotation, following up on an impressive debut in the second half of last season, and the team thought Garcia was a safer bet despite Colon's better spring numbers.
2010 Spring Training - null
Sights & Sounds
Spring Training Info
"We had seen what [Garcia] had done last year," Girardi said. "We actually felt that he had a chance to get better because he was another offseason removed from his arm issues that he had. But you still want to see it in Spring Training. For his standards, he had a great spring."
The 35-year-old Garcia had a 5.93 ERA in four Grapefruit League starts spanning 13 2/3 innings, bested by Colon's mark of 2.40 in 15 frames of spring play.
But Girardi acknowledged that Garcia was a favorite from the beginning in part because Colon, 37, has not pitched in the Majors since 2009 and is more of an unknown to the Yankees.
"Bartolo is a guy that we think can do a lot of things in our bullpen or if we needed him in a spot start," Girardi said. "He could give you two or three innings, he can give you one inning. We just think Bartolo's a lot more versatile in that role."
Of Colon's 328 Major League appearances, just three have been in relief, but Girardi said that Colon warms up quickly -- more so than Sergio Mitre, who filled that role last year and was traded to the Brewers on Friday -- and should adapt quickly to the bullpen.
Colon was excused from camp on Saturday due to illness, but Girardi said the pitcher took the news well and was happy to be on the roster. He is scheduled to begin pitching in relief on Monday against the Rays at George M. Steinbrenner Field.
Garcia said his first regular-season start in a Yankees uniform is slated for April 6 against the Twins in the Bronx.
"I've been working really hard this spring to be here," Garcia said. "They made a decision. I'm the No. 5 starter and we'll go from there."
Garcia was 12-6 with a 4.64 ERA in 28 starts for the White Sox last season. While he no longer showcases the dominant stuff that helped him win most of his 133 big league games, he has reinvented himself by changing speeds to make the most of a fastball that can be effective in the mid-80's.
"The way I feel right now is not even close to how I felt last year," Garcia said. "I feel 100 percent. I'm in good shape and it's different. I feel really good."
Girardi said he first heard Colon's name attached to the Yankees in January, when the burly former Cy Young Award winner was working for bench coach Tony Pena's club in the Dominican Republic.
Colon impressed scouts with a fastball that still pops in the low- to mid-90's and his usual effective control, which translated to his spring results -- he walked just one of the 55 batters he faced in Grapefruit League play, striking out 17.
"Bartolo was the wild card in all of this," Girardi said. "I didn't really have any expectations for Bartolo. I had no idea what to think, what he was going to do."
Injuries derailed Colon's career after he won 21 games in his Cy Young season for the Angels in 2005, limiting him to 48 games over the next four campaigns, but Girardi said the long relief role may keep him healthy.
"We will make sure that we use him properly and that we don't abuse him," Girardi said. "We understand that this is something that he's really never done a whole lot of."
Nova, 24, seemed to secure a rotation spot when he hurled six innings of perfect ball against the Orioles on March 16, striking out four. He wasn't quite as sharp on Friday, allowing two runs and three hits in six innings against the Astros.
Yet the Yankees were encouraged to see him able to win with less than his 'A' stuff -- a trait that eluded him in some of his seven starts for the Yankees last season, leading to early hooks while the team was struggling in its fight for a division title. Girardi said that Friday's effort might have been Nova's most impressive of the spring.
"[The biggest difference is] my confidence," Nova said. "Last year, in a game like that, they took me out of the game. I was thinking one pitch at a time and I feel like that was important for me."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.