"That slider ..." Chapman said with admiration. "I wish I had it. It's much better than mine. I'd be the best closer with Andrew Miller's slider. You don't need anything else."
For Miller, Chapman's fastball is beyond compare.
"Be ready for that fastball, and however hard you think it's coming, it's coming harder," Miller said. "You got to hope you're lucky. You got to hope you get a pitch and run into it. He's tough. We don't want to see him in the game.
"The goal is to try to get some runs elsewhere. He's as good as they come."
Along with Dellin Betances, Miller and Chapman spent the first half of the season together in the New York Yankees bullpen as two-thirds of the relief juggernaut known as "No Runs-D.M.C." before the Chicago Cubs acquired the flame-throwing closer in a blockbuster trade on July 25.
Less than a week later, the Yankees continued to fan the flames of their bullpen fire sale, and in turn drove the narrative of which teams would be the ones to beat in the postseason, by sending Miller to the Cleveland Indians in exchange for two of Cleveland's top three prospects.
And while the Yankees' return on these trades remains to be seen, Miller and Chapman are now the biggest weapons in their respective bullpens as the franchises seek their first World Series titles in forever -- 1908 for the Cubs and 1948 for the Indians.
"It's our job to back up the value a team places on us," Miller said. "We want to play well not only for our own sakes but to show the teams we are worth what they gave up and we want to have a chance to help our team achieve their goals.
"I am glad this worked out well for both of us. Unfortunately [Chapman] is in the way of us achieving our goal. He was a great teammate and I am glad that I had a chance to play with him."
The Chapman trade was largely expected, as the lefty was set to become a free agent at the end of the season. The 28-year-old, who went 3-0 with a 2.01 ERA and 20 saves in 31 games in pinstripes, arrived in Chicago to reinforce the only weakness the Cubs had this season: the need for closer who could get that late-inning, game-ending strikeout.
At $9 million per season through 2018, the Indians got exactly what they needed in Miller, who has now tossed 13 2/3 scoreless innings this postseason with 24 strikeouts, while holding opposing hitters to a .152 batting average. His regular season wasn't bad either as he finished with a 1.45 ERA in 74 1/3 innings in 70 total relief appearances with New York and Cleveland.
"[Miller] is a really good pitcher, very smart. He prepares a lot," Chapman said. "He works a lot on his pitches and that's why he's had the results he's had.
"I loved being in the same bullpen with him. He's very hard-working and disciplined."
While Miller has been praised this postseason for being ready to pitch at a moment's notice, Chapman has not been effective for the Cubs outside the ninth-inning structure.
"Not everybody is cut from the same cloth mentally, or has the ability to get loose and prepare," Cubs manager Joe Maddon said. "Andrew Miller, having probably done a variety of different things in the big leagues as a pitcher, is more suited to be able to be this guy that can get up in the sixth, seventh, eighth or ninth and warm up in a manner that gets him in the game both mentally and physically.
"Whether you agree with it or not, that's just the way it is."
Miller said flexibility is nothing new to him, it's just getting more attention this postseason.
"I worked my way into the bullpen over the years and I had other experiences in other roles," Miller said. "We did it a little bit with the Yankees, we were flexible for Joe [Girardi] and I think that went a long way."
No one has more admiration for what Miller has been able to accomplish than Chapman, who has had a chance to see it firsthand.
"He had been pitching more than one inning since we were with the Yankees," Chapman said. "He was doing that already. He's also more of a breaking-ball pitcher, I throw more fastballs.
"We are different pitchers."