I'm just gonna go ahead and give you guys a little science:
It's important to note that this is a preliminary measurement. Oftentimes a TV broadcast will report a certain home run distance, and then later on that home run distance will be re-evaluated and, often, reduced. We don't know for sure whether Fielder's home run took off at 119.2 miles per hour.
But let's just say that it did. In that case, yeah, hardest-hit home run of the year. You can find all that data over at the Home Run Tracker. The fastest home run off the bat during the regular season was 118.4 miles per hour, by noted thumper Sean Rodriguez. Fielder might have beat that by almost a full tick.
Appropriate that Fielder hit that home run off an 87-m.p.h. "fastball" down the heart of the plate. If any pitch deserves to get turned around super fast, it's that one.