The Pittsburgh Pirates have made it a point of emphasis with their pitching prospects this year that the fastest way to the Major Leagues isn't to speed up.
Rather it's to slow things down and take something off their pitches.
"We have a set number, a set percentage, of off-speed pitches we have to throw," said Bradenton's Mitch Keller, ranked as the No. 41 prospect on MLB.com's Top 100 and No. 2 on the Pirates' list.
The 6-foot-3 right-hander from Iowa dominated in a breakout 2016 season, relying on a fastball that hit the high 90s with sink and a curveball that was mixed in. Now Keller has to regularly use a changeup each game, and his new pitch bit him during his first Florida State League start for the Marauders this season.
Keller had stretched his regular-season scoreless streak to 31 1/3 innings when Charlotte's Jake Fraley hit a three-run homer with one out in the third inning at Bradenton on April 8.
"It was a change and I left it belt high," said Keller, who had turned 21 four days earlier.
Two singles followed and Keller was pulled after just 2 1/3 innings, eventually charged with five runs.
"I'd never really thrown the changeup that much," he said. "I worked on it after last season and then in Spring Training."
Keller, though, is getting a little more comfortable trying to keep hitters off-balance, and he's started another scoreless streak. The second-round pick in the 2014 Draft has two straight seven-inning starts without allowing a run, the first coming at Charlotte against the team that chased him early during the opening week at home.
Keller's best outing, though, was his most recent, when he allowed just two hits over seven scoreless innings while striking out nine and walking none against visiting Dunedin on Friday. The victory moved Keller's record to 3-1 and lowered his ERA to 2.88. He has struck out 34 and walked just five over 34 1/3 innings in his six starts, posting an FSL-best 0.90 WHIP.
Video: Bradenton's Keller notches ninth K
Keller, who received a $1 million bonus to pass up a scholarship to the University of North Carolina, was limited to 19 2/3 innings in 2015 because of a forearm strain and had a 0-3 record with 5.49 ERA with Bristol in the Appalachian League.
A healthy Keller bounced back in a big way last year, though. He was voted Most Outstanding Pitcher in the South Atlanta League after posting a 2.85 ERA to go with an 8-5 record and then won an early-September start for Bradenton with six scoreless innings.
That effort pushed Keller's regular-season scoreless streak to 29 innings and proved a precursor of what was to come in the Florida State League Playoffs. Keller won two starts for the Marauders, including an eight-inning scoreless outing against Tampa in the Championship Series.
It was Bradenton's first title, and Keller was a big part of it despite his late arrival.
"It was a lot of fun," said Keller, who has an older brother, Jon, in the Orioles system. "I was new to the team, but I had played with most everyone earlier. We all fit it. It was special to win a championship together."
Many of those Bradenton players from 2016 have moved up to Double-A Altoona this season. If he keeps pitching like he has his last five starts, Keller could be joining them soon.
He's learned a valuable lesson from that one bad inning in his first start.
"I have to mix in my changeup and curveball early in the count," Keller said. "I didn't have a good game plan that first game and build up my pitch count. Now I have the proper approach and the change is becoming a better pitch for me. I'm getting more confident in it."
Streak snapped: Jake Cronenworth's hitting streak -- the third longest ever for a Tampa Bay Rays prospect -- came to an end at 25 games when the Charlotte shortstop went 0-for-5 in a 2-0 victory by the Stone Crabs on May 2 at Lakeland. Cronenworth, a seventh-round pick in the 2015 Draft out of the University of Michigan, had hits in his final three Midwest League games last year for Bowling Green, going 7-for-15, and was 35-for-90 in his first 22 FSL contests this year. Aubrey Huff set the Rays' Minor League record by hitting in 28 straight games in 1998, and Darnell McDonald had a 27-game streak in 2006. Cronenworth was hitting .351 with a .450 on-base percentage through 28 games.
On the move: Bradenton shortstop Cole Tucker, Pittsburgh's No. 6 prospect, is setting a fast pace on the base paths. The first-round pick by the Pirates in 2014 swiped four bases in a game twice over a five-day period and led the FSL with 23 steals in 27 attempts. Coming back from shoulder surgery, Tucker, 20, was caught on six of 11 steal attempts in 65 games with Bradenton last season. A four-game hitless streak had Tucker's batting average down to .196 on April 18, but he was up to .254 after 29 games and had an on-base percentage of .353 thanks to 21 walks.
Settling in: Cuban right-hander Vladimir Gutierrez had a rough first two starts with Daytona but then started showing why Cincinnati gave him $4.75 million to sign last September. The Reds' No. 12 prospect struck out nine and walked none over seven innings in a 5-2 victory at Fort Myers on May 3. Gutierrez, 21, was 2-2 with a 4.10 ERA through five outings despite his early struggles and had an impressive 32 strikeouts to four walks in 26 1/3 innings. In his three most recent starts, the ratio was 23-to-0 over 17 innings. Gutierrez was a reliever in Cuba but is being stretched out by the Reds.