The veteran lefty will face the Astros on three days' rest as the Royals face Astros right-hander Jordan Lyles in Wednesday's rubber game at Minute Maid Park.
Chen, who turned 35 on Tuesday, has started on three days' rest once in his career. As a member of the Braves, he faced the Phillies on June 23, 1999, on short rest. He allowed only an unearned run in 7 2/3 innings and struck out five batters.
At that time, Chen was bouncing in and out of the Braves bullpen. But after throwing just 40 pitches and giving up six runs on seven hits in 1 2/3 innings against the Cards, manager Ned Yost opted to push Vin Mazzaro back one day and hand the ball to Chen on Wednesday.
"I didn't pitch well at all," Chen said of his last start. "I wasn't commanding my pitches. I didn't make my pitches and I got hit."
Lyles will be on regular rest for the Astros, but is also looking to get past a pair of poor starts. The 21-year old gave up five runs without getting out of the fifth inning in either of his last two starts.
Both of Lyles' last two outings began with four scoreless innings, only to disintegrate in the fifth. Manager Brad Mills said the Astros want to stop the pattern before it becomes the norm.
"He said he didn't feel like the game's getting away from him," Mills said on Friday. "He was cruising along so well and throwing the ball so well, and even some of those hits really weren't stung, but they found the holes."
Astros: Maxwell cherishing playing time
After getting picked up off waivers earlier in the season, outfielder Justin Maxwell has received more regular playing time in the last two weeks. On Tuesday, Maxwell made his 12th start in 14 games.
Since the start of that streak, Maxwell is hitting .239 (11-for-46) with four home runs. Maxwell said this is the first time he has had the opportunity to be a lineup regular in the Major Leagues since making his debut in 2007 with the Nationals.
"I'm just grateful for any opportunity," he said. "I'm thankful for the Astros. It's hard to get in a groove when you're only pinch-hitting or starting once a week. I'll just try to take advantage of it and have good at-bats."
Royals: Short bench may end soon
Manager Ned Yost hinted before Tuesday's game that the Royals may make a roster move before Wednesday's series finale. Kansas City currently has 14 pitchers on its roster, but Yost said if the bullpen performed well, a move may be in the offing.
The Royals' bullpen did its job in Tuesday's 2-0 victory, as right-handers Aaron Crow and Jonathon Broxton combined for 1 1/3 hitless innings.
With a short bench and playing in a National League ballpark, Yost had previously said relievers Tim Collins and Greg Holland are the team's emergency outfielders. Neither has yet been needed.
Though Chen has played in the Major Leagues for 14 years, Carlos Lee is the only current Astro to have ever faced him. Lee is 1-for-4 with a walk and a strikeout against Chen.