That's what I saw a lot of people saying when we replaced Bay with Cameron. But let's take a look at some of the big picture.
Catcher - This is by far the biggest offensive upgrade that the Red Sox will have going for them next year. Last year, Varitek started 109 games in which he hit an ugly .209/.313/.390 (80 OPS+). Next year, we can probably count on Victor Martinez for 100+ starts behind the dish. Victor Martinez had a rather typical year offensively last year and he hit .303/.381/.480 (127 OPS+) in 155 games between Cleveland and Boston. That's a startling gain of 47 points of OPS+ over about 100 games.
Shortstop - Before we acquired Gonzalez (44 games) we had a plethora of offensively challenged shorstops. Lugo hit a surprising .284/.352/.367 (86 OPS+), Green hit a sad .236/.303/.366 (71 OPS+) and Lowrie hit an inept .147/.211/.265 (21 OPS+). Overall, Red Sox shortstops hit a measly .245/.307/.375 which is probably good for about a OPS+ of 75. That kind of production will be replaced with Scutaro who owns a career 92 OPS+. He's likely to provide something like a 15 point boost in OPS+ over 145 games or so.
Third Base - We replaced Lowell, a .290/.337/.474 (106 OPS+) hitter over 119 games with Adrian Beltre, a career .270/.325/.453 (105 OPS+) hitter at third base. We don't really gain or lose much offense between the two. However, Lowell only played 107 games at third base. We had Kotsay (.257/.291/.324, 58 OPS+), Nick Green .236/.303/.366 (71 OPS+), Jeff Bailey .208/.330/.416 (90 OPS+) and Casey Kotchman .218/.284/.287 (48 OPS+) playing in the field for most of those games. So we can probably expect a minor boost to our offense next year.
Left Field - We replaced Bay, a .267/.384/.537 (134 OPS+) hitter with Cameron, a .250/.342/.452 (111 OPS+) hitter. That should account for something like a loss of 20 points in OPS+ over about 150 games.
So what do you think? Will our offense regress next year?