In general, most big league hitters have trouble with fastballs at or above the top of the strike zone. This deficiency is especially prevalent with left-handed hitters, who tend to have more of an uppercutting motion in their swing. Ken Griffey Jr. is a perfect example of this phenomenon.
Situation: top of the first inning, runner on first, two outs. Oakland A's starter Bartolo Colon delivers a high 1-0 fastball to Prince Fielder, who lines it into center field for a single.
The ball ends up high and inside, but Prince is able to fight off the inside pitch for a bloop hit to keep the inning alive.
Situation: top of the third, men on first and second, two outs. Colon gets ahead of Prince with a couple of fastballs low in the strike zone. On the 1-2 pitch, Colon tries to elevate a fastball on the outer half of the plate. Prince didn't miss it.
This is what FSD analyst Rod Allen refers to as "climbing the ladder." Fielder is able to both level out his swing and get the bat head around fast enough to make solid contact with what seemed to be an otherwise well-located fastball.
Situation: top of the sixth, nobody on, zero outs. In the first pitch of the inning, Colon delivers another elevated fastball on the outer half of the plate. Again, Fielder doesn't miss it.
While this fastball wasn't intended to be up -- catcher John Jaso set up at Fielder's knees -- it was in almost exactly the same spot as the pitch Fielder sent over the center field wall.
The key in both of these situations is that Fielder's strength allows him to generate excellent bat speed. Being able to quickly get the bat through the zone is crucial to catch up to elevated fastballs, so it's no surprise that Prince is able to handle the high heat.
I'm not sure what the official scouting reports are saying, but this is something that we have seen consistently from Prince since he signed with the Tigers. Most of these hits were opposite-field singles last year, so the power he showed this evening is very encouraging. If opposing pitchers continue to challenge Fielder at the top of the strike zone, don't be surprised to see Prince continue to take advantage.