Doesn't look too good to me. A couple points:
-The entire autograph seems shorter compared to other authentic Jeters
-The first two loops never cross over that much or that high on the 'D'
-The bottom loop usually connects back to the rest of the autograph and doesn't just cut off like that. Sometimes I've seen it where it looks like the pen will skip, but never at an angle like that
-The final "r" just looks completely off. Never seen a Jeter like that.

My opinion (to be administered with a grain of salt): NOT AUTHENTIC