Not quite sure why we're talking about Youk like he's the epitome of health? The guy has averaged about 120 games over the past 2 seasons. And it's not like he's going to be making a move to 1B to ease some of the physical stress of defense. He's going back to 3B, which hurt him to begin with.
You know why Youk was even a decent hitter in 2011? Fenway Park. He hit .320/.426/.563 at home in 2011, and hit .191/.317/.349 away.
Take him out of Fenway park and his numbers plummet (See: 2012 - .235/.336/.409). Even in Napoli's horrid year, he still outperformed Youk last year (Nap 2012: .812 OPS, Youk: .745 OPS).
And while we're on it, Youk had a .745 OPS last year while playing around 21% of his games at Fenway (26 games of 122 played) and posted an .848 OPS at Fenway.
Take out those games at Fenway last year? He posted a .221/.336/.388/.724 line away from Fenway Park last year.
So that's two consecutive years where his numbers are completely based on Fenway Park, yet he would have to play 1/2 of his games away from Fenway.
No thanks, I'll take Napoli, who had an .840 OPS on the road last year, had a 1.731 OPS at Fenway last year, has a career 1.107 OPS at Fenway Park, and only got stronger down the stretch when his team needed him the most (1.051 OPS in September, 7 HR in 16 games). Youkilis, meanwhile, got fatigued and his production dropped off in September, where he posted a .649 OPS and 3 HR in 26 games.
Give me Napoli over Youkilis, and it's not close.