Signing Napoli would strengthen the Red Sox in three keys areas: catcher, first base and designated hitter. It would also allow them a ton of flexibility in the next two or three seasons.
The Rangers would lose Napoli from their lineup and it would force them to expend their resources to replace him.
The Yankees have been rumored to be interested in Napoli according to a recent tweet by USA Today's Bob Nightengale. Current Yankees' catcher Russell Martin is unsigned at the moment.
Napoli would immediately fit in the middle of the Sox' order. His career slash line is .259/.356/.507 and he has hit over 20 home runs in each of the past five seasons. If Napoli could give the Red Sox similar numbers over the length of a two or three-year contract, that would really improve their ability to work pitch counts and protect David Ortiz from being pitched around.
Is Napoli a perfect fit? No, he won't be a great defensive catcher of first baseman. But with the signing of Ross, the Red Sox have improved the defense behind the plate and the ability of other teams to run at will.
They will also have two trade chips in Jarrod Saltalamacchia and Ryan Lavarnway to use in other moves to rebuild the roster.
Looking at the remaining contract for the Yankees' Mark Teixeira, he is owed $90 million over the next four years and posted a comparable slash line to Napoli last season at .251/.332/.475.
Would you rather have Mike Napoli or Mark Teixeira for the next three seasons? If you pick Teixeira, realize that you would pay twice as much for similar production. Napoli is likely to come at a commitment some $50 million less than Teixeira.
The Red Sox have also been looking at Russell Martin, according to this tweet from CBS Sports' Jon Heyman.
If the Red Sox have a choice between Russell Martin and Mike Napoli, I'd side with Napoli simply due to Martin's poor offensive production in the American League over the past two seasons.
Without a first baseman of the future in the minor leagues, signing Napoli fills a couple of short-term needs without a handcuffing the Sox long-term.
Statics from the Baseball Reference website.