Leonys Martin will be the leadoff hitter for the Texas Rangers, according to Jeff Banister (via the beat guys on Twitter).
Evan Grant specifically says that that includes leading off against lefthanded pitchers, which is noteworthy in part because Leonys has struggled against them in his major league career, and has ended up being platooned quite a bit as a result.
The interesting question now is, what will Banister do with the #2 spot? Elvis Andrus has hit there historically, but there is evidence that optimal lineup construction has your best hitter hitting 2nd, and Elvis is...not the Rangers' best hitter, shall we say.
Shin-Soo Choo is a high OBP guy who would fit well in the 2nd spot, but he's also a lefthanded hitter, and slotting Leonys and Choo back-to-back would make the Rangers vulnerable to teams utilizing a LOOGY in the late innings. Adrian Beltre could hit 2nd, though that presents the potential for Choo and Prince Fielder hitting back-to-back.
My guess is we'll see a Leonys/Elvis/Choo/Beltre/Fielder (or Fielder/Beltre/Choo) top of the order, though I'm not real confident in that guess.