Concerning Mitch Keller pattern may explain why Pirates didn't trade him at deadline

Pittsburgh Pirates starting pitcher Mitch Keller struggled to find the plate Tuesday, issuing three walks and a wild pitch during an abbreviated start against the Toronto Blue Jays.

Keller hit George Springer, the first batter he faced, with a pitch high and inside, and it only got worse from there. He got roughed up for five earned runs on seven hits in just 3 1/3 innings in the Pirates' 7-3 loss, continuing a rather unsettling trend of poor performance in the second half of the season. In six starts since the All-Star break, Keller has gone 2-2 with an 8.31 ERA with a 2.08 WHIP, and his ERA for the season has ballooned from 3.48 up to 4.34.

Of particular note during the loss to the Blue Jays was Keller's struggle to locate his slider. His spin rate on the pitch was higher than his season average according to Baseball Savant, and the Blue Jays made contact on eight of 10 swings.

"Just the command, falling behind guys and when you get ahead, being able to finish it and put guys away," manager Don Kelly said (via Eric Bowser of DK Pittsburgh Sports). "Just have to reset and get back to the drawing board with Mitch."

Mitch Keller’s second-half struggles may explain why Pirates didn't trade him at deadline

Keller has long been known as one of the Pirates' most reliable starting pitchers, and his name was at the center of countless rumors leading up to this year's trade deadline due to his value as a middle- or back-of-the-rotation starter. However, his second-half struggles are not unique to this year.

In 12 starts after the All-Star break last season, Keller went 1-7 with a 5.65 ERA and a 1.40 WHIP. The year before, he went 4-5 with a 5.59 ERA and a 1.44 WHIP through 13 starts after the break. His second-half decline has become a well-established pattern, which could explain (at least in part) why his market may have not materialized to the Pirates' liking at the end of July.

A first-half warrior isn't of much use to a playoff contender looking to make a final push down the stretch – nor is a guy who has logged zero postseason innings in his career.

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