Tim Benz: Pirates' Mitch Keller fixing shortcomings he identified

During the Pirates’ rebooted training camp at PNC Park, starting pitcher Mitch Keller identified two specific goals to hone his arsenal.

• Develop a changeup.

• Get the spin and movement on his fastball to equal its often-electric velocity.

So far, so good to start Year 2 of his big-league career.

A season ago, opposing hitters feasted on Keller’s fastball. That happened even though its average velocity was 95.4 mph and its Rapsodo spin efficiency was in the lower 90s in terms of MLB percentile.

According to Baseball Savant, Keller used his four-seam fastball 59.5% of the time in 2019. The rest of the league abused it to the tune of a .461 batting average, a .719 slugging percentage, and a .499 wOBA.

Meanwhile, Keller only threw 28 changeups last year and just two against right-handed hitters. That accounted for a meager 3.7% of his pitches. Opposing batters had a collective slugging percentage of 1.000 against it.

However, Keller’s first start of 2020 showed strides in both areas. He managed to pitch five innings and allowed just one run against the St. Louis Cardinals on Sunday. He walked three, but only allowed two hits.

That was good enough to earn a 5-1 victory, just his second win at the big-league level.

“We used the changeup three or four times,” Keller said after Sunday’s game. “Got a couple quick outs. Just changing eye level and changing tempo kept them off balance.”

As for the fastball, Keller said he struggled to hit top velocity most of the day. However, the placement and movement of it seemed to work well enough that he got through the afternoon.

“The velocity wasn’t up,” Keller explained. “We kept them off balance. But the heater played. It was playing in velocity even though it wasn’t 97 (mph). Some of the swings they were having were telling me that they were behind it because some of the other stuff we were using.”

The Baseball Savant stats show that Keller used the changeup four times, none of which were hits for the Cardinals. Its average velocity was 87.5 miles per hour.

When Keller’s fastball gets back into that 95-plus range, that difference will appear more steep to hitters. And once Keller masters the grip on that pitch — something he admits is an ongoing process — he may be able to command it with even more of a velocity dip if he prefers.

Both Cardinal hits were off his four-seam fastball. But that pitch accounted for 49 of his 86 deliveries. So the results were good overall, just a .182 batting average against that pitch for St. Louis hitters.

For his part, manager Derek Shelton also praised Keller’s slider late in the outing, which had been a useful weapon in 2019.

Shelton was just as impressed with Keller’s ability to mentally process and regurgitate those specific angles of his outing so quickly, as he was with the actual results.

“That’s a sign of maturity,” Shelton said Monday. “The fact that he can eloquently describe that to you, that’s pretty cool. The kid is just going to continue to get better and better. And he is just going to have to learn how to pitch with what he has going that day. And he did (Sunday).”

Whatever cause for optimism the Pirates can find in Keller is worth advancing. In a season where the team may have to go deep in an effort to prop up hope for its pitching staff, belief in Keller should be real.

He was touted as the organization’s top pitching prospect coming through the ranks. He’s likely the starter with the most natural arm talent in the organization. He might be the pitcher whose growth expands the most in 2020.

The right-hander’s next start is supposed to be Saturday against the Chicago Cubs in Wrigley Field. They have a 4-2 record to lead the National League Central Division. Plus, they have scored 38 runs, tops in the NL. So Saturday may be a good day for Keller to have that top velocity mixed in with some of this developing savvy.

Five innings in one game of a tricked-up season doesn’t mean he’s ready to be the next Gerrit Cole around these parts. But at least it’s a sign that Keller may have been worthy of the hype he got upon his promotion a season ago.