The addition of Randy Winn certainly gives the Yankees less offense, but more defense and flexibility (at a lower price too). Is he exclusively a bench player, or will he share time with Brett Gardner? The only position that's really set in stone is rightfield, because Swisher doesn't have the range to play anywhere else. The luxury of Gardner, Winn and Granderson are their abilities to play any outfield position.
Joe Girardi has fortunately not awarded the centerfield job to Grandy (yet). It will come down to who plays the best in Spring Training, as it should.
Gardner: we can safely say he's the best defender of the bunch. He's saved 20 runs in the outfield over 935 innings (789 in center). That's a great number, but not a great sample size (spanning less than one full season: 138 games). FRAA (Fielding Runs Above Average) also has him as a plus defender (+8 in his career).
Granderson: a good defender, no question. UZR has him as an above-average centerfielder for his career (5550 innings), but only average for the last three years. FRAA has him as above average each of the last three.
Winn: the newest addition looks to be a fourth outfielder/late-inning defensive replacement/pinch-runner at this point. His defense is solid around the outfield: excellent in the corners, below average in center. And he certainly has the experience you like to see in the 4th OFer, having played at least 20 games at every outfield position with San Francisco last year.
So if it was up to me, Gardner would be the primary centerfielder with Granderson playing left and Winn getting the occasional start along with a lot of late-inning, lead-protecting innings in rightfield.
Figuring out how many at-bats they get might be Girardi's toughest job this year.
Granderson clearly has the best bat of the trio, holding a career wRC+ of 119, including 107, 130 and 142 the last three years (is the downward trend a bit troubling to anyone else?). The tough choice for Girardi will be between Gardner and Winn. GGBG has a career wRC+ of 94, only slightly below average (his steals make up for a lot of his batting inefficiency). Surprisingly, Winn is above average, at 104, due largely to playing in pitcher-friendly parks (which suppressed his offense).
Recent history and projections suggest that, despite Winn's superior career stats, Gardner should get the lion's share of playing time in 2010. He had a higher wRC+ last year, and is projected by almost every system (CHONE, Marcel, Bill James) to have the better 2010. FYI, Granderson is projected to rebound to his 2008 season.
There's also the platoon splits. Grandy was awful against lefties last year, as was Winn. They OPS'ed .484 and .310, respectively, against southpaws. Gardner OPS'ed .781. Grandy isn't that bad for his career though (.614 OPS), while Winn is remarkably better (.758), being a switch-hitter after all. Gardner has a .627 career OPS against lefties.
How is Girardi going to weigh all that? How will recent productivity measure against career numbers?
If it was up to me, Granderson would be the everyday leftfielder. I believe his platoon stats will, along with his overall stats, rebound in 2010. Gardner gets the centerfield nod, as his defense is unmatched, and his offensive game should only improve as he gets more experience and enters his prime (he's only 26 after all). Randy Winn is on the wrong side of 30, and his 2009 offensive season left a lot to be desired. His age (35), 'switch-hittiness,' solid defense, and experience make him the perfect fourth outfielder.
All that said, I wouldn't be opposed to Winn getting the occasional start against a tough lefty in place of Granderson, or starting once a week for Gardner or Swisher (when they're slumping or need a day off).