Red Sox add players, get ... better?

So now the Sox have signed Adrian Beltre, and we know what the starting lineup looks like. They'll have new players at 3B, SS and LF, and it looks as if they've downgraded their offense. Clearly, Mike Cameron is not the offensive player that Jason Bay is, and Adrian Beltre is unlikely to match Lowell's numbers. Those could be mitigated by an almost certain upgrade at SS, where Marco Scutaro is replacing Nick Green/Alex Gonzalez.

So here's what those players did last year, the 2009 Red Sox (Bay, Lowell, Green and Gonzalez) vs. the 2010 Red Sox (Cameron, Beltre and Scutaro).

Red Sox 3B, SS, LF - 2009 vs. 2010

Player	Games	AB	Runs	Hits	2B	3B	HR	RBI	BB	K	SB	GDP	BA	OBA	SPct	OPS	RC	Outs	RC/25
2009	486	1643	234	429	98	4	67	270	167	357	18	50	0.261	0.334	0.448	0.782	238.1	1301	4.58
2010	404	1567	232	417	94	4	44	174	184	305	34	43	0.266	0.346	0.415	0.762	226.2	1222	4.63

Well, on a per-out basis, that's not a very big difference. And it's actually slightly smaller, as the Boston group had nearly 100 more plate appearances. If we look at Runs Created normalized at 1800 plate appearances, we see that the group leaving had only 2.4 more Runs Created than the group arriving to replace them. So it may not be a huge offensive downgrade.

And if we look at fielding metrics, they might even represent an upgrade. According to Baseball Prospectus' Fielding Runs Against Average, the group leaving was 4 runs below average defensively last year. The group arriving was 25 runs above average, a difference of 29 runs that dwarfs the offensive difference.


Obviously, I hate Adrian Beltre the same way that I hate Alex Gonzalez. I'm an OBP guy, and I don't like players that can't reach base safely. I enjoyed rooting for both Mike Lowell and Jason Bay. But it's hard to look at this and say that they've gotten worse, and that's without looking at the improvement to the pitching staff and the additional four months of Victor Martinez (and, more importantly, the corresponding removal of so many Jason Varitek at-bats.)