John Farrell is still not ready to reveal who the Red Sox will have in center field on Opening Day, but he will say this: if, indeed, Grady Sizemore makes the team, he won't be batting leadoff. The bulk of that role will go to Daniel Nava.
At this point, it's pretty safe to assume that this situation isn't a hypothetical. Grady Sizemore is making the team out of spring training, without a doubt. The only question is whether Jackie Bradley Jr. joins him, or heads to the minors. The latter seems, likewise, a certainty if trade interest for Mike Carp doesn't intensify in a hurry (and Shane Victorino stays off the disabled list).
Assuming that comes to pass, though, it's nice to hear Sizemore isn't destined for the leadoff spot. Instead, Farrell has tabbed him for the middle of the lineup, say fifth or sixth, citing a desire to keep him from being worn down by too many at bats early on.
Really, the reasoning behind it should be "Daniel Nava is very likely to get on base (at least vs. righties), and Grady Sizemore is a crapshoot," since the latter hasn't managed to do so consistently since 2008. But John Farrell can't come out and say that even if he wanted to, so it's not worth reading too much into the thought process provided.
Even given that reasoning, though, Sizemore batting sixth actually isn't that unusual. Boston's 6-7-8-9 bunch almost certainly consists of Xander Bogaerts, Will Middlebrooks, A.J. Pierzynski, and Grady Sizemore. Not a one of them is a guarantee to produce offensively, and frankly Sizemore probably ranks higher than Pierzynski and Middlebrooks in terms of how likely they are to have an above-average offensive season.
Simply put sixth is around where he probably should be batting, at least to start. It may well turn out that he's as good as ever and belongs higher, or that he gets beaten out by Bogaerts and Middlebrooks (and maybe even Bradley). But at least for April, sixth is about right.