UPDATE: Jeter is good to go, and Brian Cashman didn't even have to tell anyone to STFU:
#Yankees clear Jeter to begin rehab assignment. WIll join Triple A Scranton/WB tomorrow and is scheduled to play at least 5 innings at SS.— Ken Rosenthal (@Ken_Rosenthal) July 5, 2013
So Jeter will finally test his ankle and his 39-year-old's range at shortstop. All the issues discussed below still obtain -- the Yankees have gotten little offensive production out of their shortstops this year, and Jeter should be able to top them even if he's half the player he was. The real question is his ability to play defense.
Via the New York Daily News:
"I'm anxious to be playing in games," Derek Jeter said. "Everything I've needed to do up until that point, I've done... I think I'm close."
That said, the Yankees infield has been on the porous side already: only the Tigers have allowed a higher batting average on ground balls than the Yankees' .261. Compare that to their AL East rivals: Baltimore leads the league at .216, the Rays are third at .226, the Red Sox are sixth at .236, and the Blue Jays are 10th at .247. That's not all on the shortstops, but they haven't been good -- Nunez is an error machine; Nix is merely steady. Ironically, "merely steady" is probably more than we'll be able to say of Jeter at this point.
Whether Jeter will be a net positive at that point will depend on the interplay of his offense and defense -- a grounder past a stationary shortstop is just a single, after all, and if the shortstop hits enough doubles and home runs his team will be more than even. We can also wonder about the interplay of all the gloves in the field -- if you add a slow shortstop to a third baseman with no hips (Alex Rodriguez) and a first baseman whose best defensive days are behind him (Lyle Overbay), at what point do you achieve a kind of critical mass where the pitchers have a right to revolt?
We'll get some sense of Jeter's defensive abilities as soon as he's cleared to play in actual games. You'll hear more about how many hits he's getting, but the real proof will be in whether his first step, which was always more of a thoughtful, high-effort trudge after balls to his left, is now something you can time with a sundial.