CLEVELAND -- Corey Kluber's curveball is not only his best pitch, but one of the top weapons in baseball. After a rough start to the season, a five-week span plagued by inconsistency and injury, the Indians ace has turned to that pitch at a higher rate than at any point in his career.
The results have been stellar. In five June starts since coming off a month spent shelved with a back issue, Kluber has posted a 1.29 ERA with 52 strikeouts, six walks and a .400 opponents' OPS in 35 innings. In four of those starts, the righty's curve was his most-thrown pitch. Prior to June, Kluber's breaking ball was his No. 1 pitch in just one of 140 career regular-season starts.
"It's the evolution of him as a pitcher," Indians pitching coach Mickey Callaway said on Sunday morning. "We saw a few years ago that we'd sometimes try to get through the first time through a lineup with a ton of fastballs to kind of set everything up. And at that time, we were still working on fastball command and things like that. And now, teams are taking a different approach.
"He's Corey Kluber, the Cy Young winner. They're coming out swinging really early. Early in the game. Early in the count. We just don't think it's smart to hold on to his best pitch until later in the game like he has in the past. So, he's coming out of the gate throwing a lot."

According to Statcast™, batters have hit .086 with a .123 slugging percentage against Kluber's curve this year, and .114 with a .171 slugging percentage over the 2015-17 seasons. The MLB averages against right-handed curveballs are .219 (batting average) and .363 (slugging) this season, and .215 (average) and .350 (slugging) over the past three years combined.
Even with a month spent on the disabled list, Kluber ranks first in the Majors with a 12.5 pitch value for his curve, according to Fangraphs. Over the 2014-17 seasons, Kluber leads baseball in that category with a 72.6 rating, which is well ahead of the second-best curve in that span (33.2 by Clayton Kershaw).
While Kluber was sidelined, Callaway went to work on analyzing the right-hander's first six outings, which resulted in a 5.06 ERA and a .799 opponents' OPS for the ace. Since being activated, Kluber has dropped his two-seamer use to 24.5 percent from 41.6 percent and increased his curve rate to 30.1 percent from 19.9 percent. Kluber has also ticked up his cutter use (24.7 percent post-DL and 18.5 percent pre-DL).
"We looked at all the numbers," Callaway said. "I think I've looked at every number possible in the last month to try to figure out what can make each starter better. That was one of the things that came to mind when we were looking at Kluber's numbers, was, 'Hey, let's not hold on to that pitch. Let's make sure we use it enough.'"

Worth noting
• Indians outfielders Brandon Guyer (left wrist) and Michael Brantley (right ankle) are nearing a return from the DL. Guyer was scheduled to play a Minor Leagur rehab game with Triple-A Columbus on Sunday and could be activated as early as Monday. Brantley went through running drills on Sunday and is scheduled to run the bases on Monday before being re-evaluated.
• The Indians re-signed utility man Michael Martinez to a Minor League contract on Sunday and assigned him to Triple-A Columbus. This marked the fourth stint with Cleveland for Martinez, who was designated for assignment by the Rays on Monday before electing free agency.