Chapman, Doolittle win Relievers of the Month

Left-handers on postseason-bound Yankees, Nationals dominated in September

Chapman, Doolittle win Relievers of the Month

Aroldis Chapman of the Yankees and Sean Doolittle of the Nationals, two All-Star left-handers who took surprising paths to closer roles on postseason-bound clubs, were named The Hartford American League and National League Relievers of the Month for September, respectively. The awards were announced on Monday by Major League Baseball.

Chapman posted a scoreless September while allowing only three hits and two walks over 12 innings, regaining his ninth-inning role. He retired 36 of 41 batters, with 17 strikeouts, a .077 opponents' batting average and six saves over 11 appearances. Chapman's legendary fastball averaged 100 mph this season, leading the Majors and marking the fourth straight year he has averaged in triple digits.

Chapman credited Yankees pitching coach Larry Rothschild and bullpen coach Mike Harkey, as well as bullpen mates David Robertson and Dellin Betances, for helping get him back on track in September.

"When things weren't going right for me, they were always there to give me confidence," Chapman said. "They're the reason why I was able to get my command back and my control back."

According to Statcast™, an improved spin rate has made Chapman's elite heater even more dominant lately, one likely reason for the resurgence. Nine of his 15 best outings of the season in terms of average spin rate on his fastball came in September. Paired with an uptick in velocity, opponents are back to missing on a ton of their swings against the left-hander.

Statcast: Chapman's blazing K

Through Aug. 31, his average fastball was measured by Statcast™ at 99.8 mph velocity, 2,482 rpm spin rate, and 23.5 whiff percentage. Since Sept. 1, those respective numbers were 100.8, 2,544 and 39.1 percent.

Chapman earned a World Series ring last fall for the Cubs and then returned to his former Yankees team. Doolittle, meanwhile, was acquired by Washington with Ryan Madson in a July 16 trade with Oakland for Blake Treinen and two prospects, and proceeded to lock down the Nationals' closer role.

While Chapman gradually became his old self on September, it was a rather odd contrast to how Doolittle finished up the month on the NL side.

On Thursday night against Pittsburgh, Doolittle blew his first save as a National after converting 21 of 21 opportunities. He came in to preserve a 4-2 lead in the ninth, and Josh Bell touched him for a two-run homer. Washington bailed Doolittle out on a walk-off hit, but in the big picture, it was just a blip on an otherwise brilliant September -- and a good one to get out of the way before the NL Division Series arrives against the Cubs.

Doolittle said after the game that it served to "remind myself that from the first pitch coming in, you have to be ready to go. You have to have that killer instinct. You have to have that aggressive mindset."

Which is what he had for the rest of the month.

Doolittle wins NL Reliever honor

Doolittle made 11 appearances in September, finishing with eight saves, 14 strikeouts, three walks, an 0.82 WHIP and .158 average-against. Since 2012, he ranks first among all Major League left-handed relievers and 10th among all MLB relievers with 1.75 walks per nine innings. He finished the season ranked season in the NL with 21 saves since the All-Star break, especially lethal against lefties (6-for-41, .146).

Doolittle gets it done in a different way than Chapman, but his fastball has still been effective. Bell's homer was a big exception to the rule, as batters rarely Doolittle hard. According to Statcast™, the average exit velocity against his fastball is only 83.1 mph, third-lowest among relievers with 100 batted balls.

The award is an extension of MLB's partnership with The Hartford, which annually presents the Mariano Rivera AL Reliever of the Year and Trevor Hoffman NL Reliever of the Year awards. The winners are determined by a panel of industry experts.

Mark Newman is enterprise editor of MLB.com and a baseball writer since 1990. Follow him @Marathoner and read and join other baseball fans on his MLB.com/blogs hub. This story was not subject to the approval of Major League Baseball or its clubs.