What was interesting about Justin Morneau’s second home run of the game yesterday (and the walk-off winner which John Bonnes detailed here) is that it happened to be just his third home run he has hit which was thrown over 90 miles per hour this year.

On his second homer of the year back on April 18, he turned on a 91.7 mile an hour Hiroki Kuroda fastball. On July 6, he redirected a 96-mile an hour Tanner Scheppers fastball into the Rangers Ballpark stands. Yesterday’s walk off that came on Vinnie Pestano’s 91 mile an hour fastball marked just the third time this year that he’s managed to put a 90+ fastball into the seats.

In 2009, when Morneau was a sure-fire MVP candidate before missing the last month of the year, 14 of his 30 home runs came on fastballs over 90 miles an hour. In 2008, eight of his 23 came on fastballs over 90 miles an hour. Now, just three of his 19 home runs have touched that velocity.

The tendency may be to associate this with his concussion, however, during the 2010 season Morneau hit just two of his 18 home runs on 90+ fastballs as well. Perhaps it is a byproduct of aging, or the injured wrist, shoulder or other ailment.

Consider his hitting zone against the fastball in the first half compared to the second half of the year:

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With the green-to-red colors representing the greater production, Morneau’s second-half performance (depicted on the right) shows that he has much better zone coverage against fastballs. Take note of the dramatic difference between his first-half production (left) when being thrown inside in comparison to the second-half (right), in which he was handling the inside fastball far better.

Independent of what leaves the park, Morneau’s performance against fastballs overall has improved as the season has gone on.