The tinkering began around the All-Star Break, an idea evolving into something larger. Kelvin Herrera was searching for something, an elusive tertiary option to supplement his arsenal.
He did not need this, of course, at least not desperately. For the last three seasons, Herrera had been one of the American League’s most dominant relief arms, squeezing the life out of opposing offenses and bolstering a lethal Royals bullpen. He wiped out hitters in an uncomplicated manner: Pure gas and a power change.
From 2013 to 2015, Herrera’s fastball averaged 98.1 mph, second fastest in all of baseball behind Cincinnati closer Aroldis Chapman. Herrera’s change-up served to induce grounders at a high rate, preventing batters from cheating on the heater.
But as the season hit late summer, Herrera began experimenting with a pitch he’d rarely used during his career — a slider. In the weeks that followed, as he worked to refine the pitch with Royals pitching Dave Eiland, the results were varied. He struggled to command the slider for strikes. He struggled to conceal his off-speed delivery.
“I (didn’t) always have the best feeling in those two months,” Herrera said.
Six weeks later, that appears to have changed. As the Royals arrived in Toronto on Sunday, just two victories from a return trip to the World Series, Herrera credited the advancement in his slider to a heretofore excellent postseason. In five innings over five appearances, Herrera has allowed just one run and racked up 10 strikeouts. His only blemish came in Game 4 of the AL Division Series at Houston, when he opened his second inning with a walk and the run would come around to score against reliever Ryan Madson.
“I got the slider working now,” Herrera said. “That was a pitch that I don’t have the total dominance of. Now I feel like … much better.”
The latest example: Herrera’s scoreless eighth inning during the Royals’ 6-3 victory in Game 2 on Saturday. During an 11-pitch appearance, Herrera threw four sliders, sitting down Toronto’s Edwin Encarnacion and Russell Martin with strikeouts.
“The hitters know that I throw hard,” Herrera said. “It’s important to have a secondary pitch.”
On the whole, Herrera has backed up his lights-out postseason in 2014, when he allowed just three earned runs in 15 innings. He has sparked a Royals bullpen that has suffocated the Blue Jays offense in the series’ first two games. He has also quelled any lingering doubts after experiencing some late-season hiccups.
Herrera, who posted a 1.41 ERA last season, was nicked for seven runs in September, posting a 6.75 ERA in 10 appearances. It was a tiny sample size, but as the postseason loomed, it was still mildly disconcerting. Six of those runs, though, came in consecutive appearances, and Herrera finished the season with seven scoreless outings in his last eight appearances.
More important than the numbers, Royals manager Ned Yost says, was the rest Herrera received as the Royals held the AL Central race in a vise-like grip. A rested Herrera is a man who can live in the triple digits with his fastball. And before the postseason began, Herrera had pitched on back-to-back days just twice since Sept. 1.
“We were able to manipulate the last three weeks preparing for this time,” Yost said, “Knowing that: ‘Hey, these guys are going to go two days in a row and quite possibly could go three days in a row because they're that good.’ ”
The rest has proved beneficial for Herrera, who utilized another day off Sunday as the Royals conducted an afternoon workout at the Rogers Centre. In 24 hours, the ALCS would reconvene, and the Royals bullpen would head back to work.
In two games against the Blue Jays, the Royals’ corps of relievers have thrown 6 2/3 scoreless innings. Two of those innings belonged to a reinvigorated Herrera, who has found some October zen after finding a new pitch.
“I’ve been feeling pretty good lately,” Herrera said. “It’s important to have those days off (where) we can get our arms fresh.”