It's true that the Yankees would need an arm, especially if they want to go up against the All-Star-loaded Boston Red Sox. However, Jimenez would not be much of an upgrade for the starting rotation.
It's simply not worth it to get him.
Jimenez struggled too many times in the second half of the season last year, and owns a mediocre ERA of 4.20 in 2011. One can make an argument that he pitches half his games at Coors Field. Well, Yankee Stadium isn't close to being a pitcher's park, either. He would also have to go up against AL East offense most of the time.
You can think of him as an A.J. Burnett: dominant like a Cy Young Award contender for some time, then pitching like a No. 5 starter on a last place team. The Yankees can't afford to add another inconsistent arm when they already have one.
The Colorado Rockies' asking price for their starter doesn't come cheap, too. According to Joel Sherman of the New York Post, the Rockies are asking for three prospects out of Jesus Montero, Dellin Betances, Manny Banuelos and Ivan Nova.
Brian Cashman is still reluctant about moving Montero (where others believe he should be moved while he still has value), and pitchers Betances and Banuelos are considered top pitching prospects in the organization. It's certainly not going to be easy to satisfy all fans and the future if the deal is to be made.
This also brings us to another topic in Nova. Nova, who was pitching solid with an 8-4 record with a 4.12 ERA, was sent down to Triple-A as a controversial move to make room for Phil Hughes. The Yanks' main reason seemed to be that they wanted Bartolo Colon and Freddy Garcia to remain in the rotation. However, that contradicts the rumors.
Why would the Yankees go after Jimenez, if they feel their current starters are better than Nova who owns a better ERA? Keep in mind, Jimenez is being compared to a Triple-A starter.
Even if the Yankees do indeed believe that Colon and Garcia won't be able to keep up with their pitching, they have many other options in Sergio Mitre or Nova.
It just doesn't add up that the Yankees are even considering Jimenez.