Range factor is an awful measuring stick for defense, especially with that sample size. In fact, his current sample size renders most defensive stats meaningless at the moment, but I will throw in the fact that Denorfia did post a .909 zone rating in center field last season, whatever that's worth given the sample size. Freel's was .877, and Griffey's was .822.
I know Denorfia's BA rating, and I've seen Denorfia's defense in person so I can verify that he deserves every ounce of that BA rating. Like M2 said awhile back, Denorfia's break and line to the ball is just simply pretty to watch.
I posted the following a month ago, and it still stands ...
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Freel's an above average defensive center fielder, and he's willing to dive for everything that's within his reach. Those are the plays people remember, and it's always the end of said plays that get the highlights. The problem is Freel's initial jump on balls is actually rather lousy, and the initial jump is something you'll rarely see on TV yet it's plainly visible from the box seats. His biggest problem is immediately judging the depth of a fly ball. He'll break in on balls that'll go over his head, and he'll break back on balls that wouldn't reach his position. One result of those bad jumps is some of the diving catches Freel makes wouldn't have required a diving catch if he had read the ball correctly off the bat initially. Luckily, Freel has the speed to oftentimes make up for his poor first read, though sometimes his bad jump has cost him.
Denorfia gets a much better jump on balls in the outfield than Freel, and he'll also take a better direct line to the spot on the field he has to be at to make the catch. He is the exact blueprint any team would want in a center fielder defensively, because he does everything very well defensively. The downside is if you're stuck watching him on television, you're robbed of seeing half of what makes Denorfia a great center fielder since you'll never see his first jump, where he was at in center when the bat made contact with the ball, or his full, direct line to the ball; you'll only see the end of the play as he's gliding over to make what looks like an easy grab.
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As for the Reds playing Denorfia around the outfield instead of specifically and only in center field, that's what the Reds used to do in their system a few years ago, and they may still do it now to a degree. They did it with Kearns, Dunn, Pena, and Denorfia so I wouldn't read anything into it. Last season, 76 percent of Denorfia's defensive innings came in center field, though. Jay Bruce last season split his time equally between center and right.