Out of 15 big league appearances since his Aug. 31 debut, Chapman worked back-to-back four times -- and just once three days in a row. On those occasions, his velocity tends to dip below 100 mph more often, or he will rely less on his fastball.
"That is something we've come to learn. He went three days in a row and he was a little tender and we had to shut him down," Reds manager Dusty Baker said on Sept 25. "This is something new to him, and his arm too."
On the games he has thrown back-to-back days, Chapman has had mixed results. On the day after he reached 105, he was back out for the bottom of the ninth inning of a 3-3 game. The 22-year-old had a 1-2 count on Chase Headley but walked him with a full count. With two outs, Chris Denorfia scorched a walk-off RBI double down the left-field line.
Also, it could be best for the Reds if Chapman is brought in to start an inning rather to put out a fire during one. He has allowed five of his eight inherited runners to score. On Sept. 11 vs. the Pirates, on his third straight day of work, Chapman entered in the middle of the eighth with runners on second and third and gave up a Neil Walker two-run single up the middle.
With the breaks in this series, the Reds could easily make use of Chapman in every game against the Phillies.
"I think there are certainly benefits to that," pitching coach Bryan Price said on Tuesday. "Other guys in our bullpen have a very good understanding and experience with coming out of the bullpen on consecutive days, three days in a row and things. Aroldis hasn't a great deal."
Of course, it works both ways. Phillies relievers also get a break between games. Then again, no one on the Philadelphia side of the bullpen can touch 105 mph.
"We've seen a good amount of guys who've thrown 100," said Phillies left fielder Raul Ibanez. "We've never seen anybody throw 105. You've got to get a good pitch to hit, and do your best to hit it hard. That's what the focus is."
"Your bat has to be a little quicker," said Phillies third baseman Placido Polanco. "It's not simple, but you have to make that adjustment."
Speaking to reporters at a pre-workout press conference on Tuesday, Chapman did not believe his velocity would be an overwhelming advantage.
"Because in baseball, you have a lot of tools that you can use," Chapman said through interpreter Tomas Vera. "You can use video. There are cameras everywhere. The players have a chance to look at you and they can make adjustments. So they can know what I have and they can see me through video."