I have always been a fan of Youkilis, but do not want him back for sentimental reasons only.
The Napoli discussions sound like it is going to take a four year contract to get him to come to the Red Sox, and I do not really like the idea of giving him a three year contract for whatever cost (I am guessing somewhere between $11 and 13M per year).
This guy is not really an option at catcher as both Lavarnway and Saltalamacchia are at least as good as Napoli is right now and both are likely to at least stay at their current capacity as defenders (and, they might get better) while Napoli is likely to drop off even further as a catcher much more than he is likely to even stay at the same level.
With that said, he is a first baseman/DH. On the Red Sox he is not really needed as a DH if David Ortiz can come back healthy by April as Ortiz has seemingly solved his problems with hitting the lefties that plagued him for a while a few years ago. He is not likely to play many games at first base in the next two years so he is not going to need too many days off to rest.
As a first baseman, Napoli is not highly regarded defensively, AND it seems like he thinks that he is still a catcher. How happy is he going to be with not catching but maybe one time a week? Ross and either Saltalamacchia or Larvarnway catching are not going to leave many games for Napoli to catch.
This guy is coming off a down year, he is not an ironman (neither is Youkilis) type player and I think that it is too big of a gamble to go with him at his age, offering no speed and having defensive weaknesses at the two positions he plays to give him a three year contract (never mind a four year deal) at over $10M per season.
Here is where and why I think that Youkilis would be a much better option. He is also coming off a bad season and will likely sign a one or two year contract for somewhere about half of what Napoli is likely to get. He hit 19 HRs last year in his down year so the power difference is not likely to be huge. He knows how to play in Boston pressure cooker, and we do not know if Napoli will be able to adjust from the laid back places (Anaheim and Texas) he has played to the Boston atmosphere.
Youkilis also offers no speed and can only play two positions (just like Napoli), BUT he plays a MUCH better first base than Napoli will ever play even if Youkilis is a little older.
Loney may be a nice guy with a decent glove, but he is not the answer. Laroche is too expensive (salary, years and draft pick). Middlebrooks could be the first baseman in 2014 or 2015 or whenever Bogaerts arrives.
Youkilis is a very emotional guy, and I will never blame him for not liking what Valentine did to him last spring, but the unprofessional Valentine is thankfully gone. There will be no such clashes between Farrell and Youkilis. Youkilis returning would be a much better choice at first base than Napoli.
Youkilis: far, far superior defense, pretty equal power, equal durability, equal OBP, much less expensive, shorter contract length, etc, etc