Indeed, what you see is what you get, the aging, injury-plagued Colon trying to shore up an otherwise very young rotation, although Sox general manager Ken Williams wouldn't rule out another addition through trade or free agency.

"We'll see," was Williams' response when asked.

Basically, the Sox replaced the relatively guaranteed wins of Javier Vazquez -- who was traded to Atlanta for catcher Tyler Flowers, infielder Brent Lillibridge and others -- for Colon's what-if.

Vazquez, 32, was 38-36 for the Sox the last three seasons in 6272/3 innings. In the same span Colon, 35, was 11-15 in 1942/3 innings. Yet it was the potential that comes with the 2005 Cy Young Award winner that has Sox brass hoping they spent $1 million (and up to three times that with incentives) wisely. Vazquez is owed $22.5 million over the next two years.

"Everyone knows what Bartolo can do when he's healthy, and with all the [medical] information, we just felt he was on the other [side] of his [injury] issues," Williams said.

Colon had arm problems and was sidelined much of last season with back problems. He also is listed, probably kindly, at 250 pounds. But the Sox know they have a major rehab project on their hands, one that might take more than just the spring.

"Basically, we have to get his body in the best shape it has been ... and get his arm strength back," pitching coach Don Cooper said. "He's not where he needs to be in either case. ... If it takes him another start or a week [after spring training], I'm willing to do whatever we have to do to get him ready. Kenny got us a guy who can help us win."

Colon will be penciled in behind Mark Buehrle, John Danks and Gavin Floyd.

dvandyck@tribune.com