If this is what is preventing the Rangers from signing Fielder, then they are making a mistake.
Josh Hamilton is a very, very good baseball player. Nobody is doubting that. There are a few problems when it comes to re-signing Hamilton. First and foremost, he's already on the wrong side of 30 -- and he's injury prone. Hamilton isn't suddenly going to become more durable the longer his career goes on, and his injury proneness is what it is at this point.
Secondly, and perhaps most importantly, he simply isn't going to be worth the money he collects from his next contract.
Hamilton is a very good baseball player as I said before, and he seems like a great guy. He's very easy to root for, and his comeback story is pretty remarkable.
Still, Hamilton is not an 8.5 WAR player like he was in 2010 when he won the American League MVP award. That year, Hamilton's BABIP was an unsustainable .390, and it dropped all the way down to .317 in '11 -- which is about right. In 2011, Hamilton posted a 4.2 WAR, which is much more the ballpark he's in rather than 8.5.
And there is absolutely nothing wrong with that. Hamilton is a very good baseball player. He is not, however, going to be worth a Jayson Werth-esque contract next offseason, headed into his age 32 season. He simply isn't. Sure, he might put up another ridiculous 7-8 WAR season a year or two into that contract, but over the life of it, he is not going to live up to the monetary expectations. He's going to decline at some point, and he's going to continue to get injured.
Signing Prince Fielder to a long term deal certainly makes more sense -- and that way, you'd get to enjoy 2012 with both Hamilton and Fielder in the same lineup. Fielder turns 28 this year and is entering his prime, and there is no reason to think that he won't be highly productive for the next five or six years.
It's pretty easy to see that signing Fielder rather than giving Hamilton an extension not only gives the Rangers the best chance to return to the World Series in 2012, but it is easily the safer longterm play for Texas.