Drew Pomeranz and his cutter are back

On July 28th, just three days before the trade deadline, the Red Sox placed David Price on the disabled list with an elbow injury. Many were calling for Dave Dombrowski to make a big starting pitching splash to fill Price's void, not knowing how long he would be shelved despite assurances it wouldn't be long. Dombrowski made no such move, despite a below average offense (94 wRC+) and a rotation full of question marks behind Chris Sale.

MLB trade deadline: Swarzak traded from White Sox to Brewers

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The rebuild continues apace on the South Side of Chicago, while the Brewers focus on their surprising opportunity and make a win-now move.

Dombrowski's decision hold tight at the deadline and stick with the July 31st rotation has hinged heavily on his confidence in Drew Pomeranz.

The twenty-eight-year-old left-hander has been one the best starting pitchers in the American League this year. His 3.69 fielding independent pitching is 9th-best in the AL and his 3.36 earned run average is 8th-best. He is outpacing Chris Archer and Michael Fulmer in ERA, and Yu Darvish and Marcus Stroman in FIP.

Pomeranz is no stranger to success. He has been the 35th-best pitcher among those with over 400 innings pitcher according to Fangraphs' fielding independent pitching measure. He hasn't posted an ERA over 4.00 since 2013, over that stretch he has never had a K/9 under 8.00 or an HR/9 over 1.20.

Pomeranz got his big break last year when the San Diego Padres awarded him his first full-time rotation spot. He turned his chance into an all-star appearance and a 2.47 ERA at the break. The Padres pounced on the opportunity to flip his breakout for a young prospect.

He followed up his stellar first-half with a stinker of a performance with the Red Sox, posting a 4.59 ERA in 68.2 innings, and failing to make the Red Sox postseason rotation.

Some would point to injury concerns as the cause of Pomeranz' struggles with the Red Sox, despite making it out to the mound every fifth day without any DL trips. When healthy however, few doubt his effectiveness.

The real reason for Pomeranz' struggles in the second-half last year, and for his early-season struggles this year, was his lack of utilizing his cutter.

He discovered the pitch while playing catch in Spring Training 2016. He rode the pitch to his early success in 2016. The offering gave him another look besides his fastball and excellent curveball.

But something happened when he joined the Red Sox. He slowly stopped using it.

In June of 2016, he used his cutter 20.08 percent of the time, by September with the Red Sox, he used it just 9.35 percent of the time.

Pomeranz started off 2017 exactly where he left off last year. He threw his cutter just 2.31 percent of the time in the month of April, which resulted in a 4.15 ERA average. He didn't throw his cutter more than six times in a start until his outing against the Texas Rangers on May 25th, when he threw it twelve times. Since that start, he has thrown his cutter almost ten percent of the time.

Good results have followed. His ERA is 2.61 since May 25th, which is 6th-best in the league over that stretch among those with over 50 innings pitched. The pitch has transformed him into one of the best pitchers in the league on two different occasions now.

Pomeranz still relies heavily on his fastball and curveball, he has thrown one of the two pitches 86.26 percent of the time so far in 2017, but the cutter gives hitters a different look besides the usual two pitch mix. It's that third pitch that so many relievers struggle to find in order to make the jump to becoming a starting pitcher.

He throws his curveball a slow, looping 79 MPH, while his fastball hovers around 92 MPH. His cutter comes in around 86-87 MPH.

Although hitters are having success against his cutter this year (.529 SLG this year vs. .377 last year), he is still enjoying what might end up being the best year of his career. Even if he doesn't return to his 2016 success as far as outcomes go with his cutter, the added dimension to his repertoire makes his curveball and fastball so much better that it might not even matter. It's scary to think he has even more room to improve even after his dominant two month stretch.

Dylan Svoboda is a writer for Beyond The Box Score and BP Milwaukee. You can follow him on Twitter at @svodylan.