John Farrell has probably picked his leadoff hitter, but it would make sense to look elsewhere
Before the 2012 season, there were rumblings of a possible change in the Red Sox lineup. Jacoby Ellsbury, who had led off for the club previously, even during his fantastic 2011, was considered possibly a better fit for somewhere else in the lineup, such as third. In the end, though, because of the lack of viable alternatives available, it didn't make sense for Ellsbury to hit anywhere but the leadoff spot. This was all made moot by his injury, but we're speaking strategically.
Enter 2013, with a new manager around, and the question comes about once again: who is going to hit leadoff for the Red Sox? John Farrell has already tipped his hand, according to Evan Drellich and Ian Browne of MLB.com, suggesting that Ellsbury will once again be the man for the job. Farrell also suggested it's going to be Shane Victorino who bounces around the lineup often, given how good he is against left-handed pitching:
"The one variation to look at is against a left-handed pitcher. You can see Victorino in the two-hole against a lefty, you can see him down in the five-, six-hole in that area [against a righty]," Farrell said. "But I think the one thing that stands out is with [Stephen] Drew's addition and now [having Mike] Napoli, it gives us that complement and that balance left and right all the way through the lineup."
The more at-bats against left-handers for Victorino, who is a career .301/.373/.508 hitter against them, the better, and the opposite holds true for righties. (In fact, hopefully Farrell realizes he has Will Middlebrooks to bat sixth against righties instead of Victorino.)
This is an understandable route to take, given Ellsbury's familiarity with the role, but, unlike for 2012, there is a viable alternative to consider. Two, in fact. And it would conveniently fit in with Farrell's idea of moving hitters around based on the handedness of the opposing pitcher, too.
Daniel Nava is very likely going to be the starting left fielder for the Red Sox against right-handed pitching. Nava's career line might be a little lower than what he can actually produce, given he played through a wrist injury for much of 2012, but even with that, he owns a career on-base percentage of .352 overall, and .369 against right-handed pitching. The Red Sox, as a unit in 2012, produced a .304 OBP, and didn't make up for it with power, either. If Nava were to leadoff against right-handed starters, and all he managed was his career line in games started by righties (.251/.351/.380), Boston's leadoff situation would be in a much better place than 2012 even if they didn't have a great leadoff option for southpaws.
The thing is, though, they do, as you already know since you saw Victorino's numbers against left-handers. Nava against righties, Victorino against lefties, with Jonny Gomes -- the platoon mate of Nava -- taking over for Victorino lower in the lineup on those days. Ellsbury could be shifted to third in the lineup regardless of handedness -- if he's healthy, he's going to hit, and if he's not healthy, well, you need a new leadoff hitter anyway. That would give the Red Sox something like Nava, Dustin Pedroia, Ellsbury, David Ortiz, Mike Napoli, Middlebrooks, and Victorino against right-handers to start, and Victorino, Pedroia, Ellsbury, Ortiz, Napoli, and Gomes or Middlebrooks against southpaws. With the right platoon splits featured, that's a more than potent first seven, and when you toss Jarrod Saltamacchia and Stephen Drew in their respective slots, it looks even better.
It's possible that Farrell wouldn't want to have two left-handed hitters in a row in Ellsbury and Ortiz against their fellow lefty, but Ortiz seems to be over the can't hit lefties portion of his career, and Ellsbury is a career .298/.350/.412 hitter against them, making him more than up to the task.
This is unlikely to occur from the start of the season given Farrell is already talking about Ellsbury leading off, but Nava was already Boston's best option for the role in 2012 once he entered the picture, and, to start 2013, he's once again picturesque for the role given his patient approach and the fact Ellsbury can likely fit in elsewhere. If the season doesn't begin this way, it could still theoretically end up where it belongs, especially if Ellsbury's power game thrives once more.