Chen gave up six runs in his one inning of work, and the Royals went on to costly 11-5 loss to the Minnesota Twins on Thursday night.
"I didn't make good pitches and they get base hit after base hit after base hit," Chen said.
Kansas City's lead in the AL Central was trimmed to one game over Detroit, which beat the Yankees 3-2 earlier in the day. Third-place Cleveland also won, pulling within 5 1/2 games of the Royals heading into their big series this weekend.
The Royals were in good shape after Gordon led off the seventh with his 17th homer, tying it at 5 with a drive to center. But that was their last run of the game.
"It would have been one of those great wins for us when we didn't get a good pitching performance, but the offense picked it up," Royals starter Jeremy Guthrie said. "It would have been a late win, so it would have been a great win. As it is, it's a loss and we'll go on and not think much of it tomorrow. Certainly the team as a whole did everything it could to make this a win in spite of the early pitching troubles."
Guthrie allowed five runs and nine hits in six innings. He was 5-1 in his previous six starts.
Jordan Schafer tied a career high with four RBIs for Minnesota, including a two-run single in the 10th inning.
Chen (2-4), the sixth pitcher for the Royals, walked two and allowed five hits.
"It was another one where we could have won or lost," Twins manager Ron Gardenhire said. "We could have won all three or lost all three. Tonight was no different. We hung in there and finally had the big inning. It was a nice win for us after two tough losses."
Minnesota had lost its last four games against Kansas City and seven of eight overall in the season series. Schafer had three hits while extending his hitting streak to eight games.
"Bruce just couldn't put 'em away," Royals manager Ned Yost said.
Anthony Swarzak (3-1) picked up the victory.
ROYALS ADD NIX
The Royals claimed INF Jayson Nix off waivers from the Pittsburgh Pirates, where he was 4 for 36 in 16 games. Nix, 32, began the season with Philadelphia and also played in the minors with Durham, the Rays' Triple-A club.
Royals RHP Kelvin Herrera pitched the eighth to extend his scoreless inning streak to 23 1-3 innings.
Twins: 1B Joe Mauer didn't start for the first time since returning Aug. 11 after missing 34 games with a right oblique strain. "I watched him last night," Gardenhire said. "I thought he was dragging a little bit. You've got to do it for him. He's in the training room, getting treatment every day like everybody else." Mauer walked as a pinch hitter in the 10th and stayed in the game to play 1B.
Royals: LHP Scott Downs (stiff neck) was activated from the disabled list. ... 1B Eric Hosmer (fractured right hand) participated in batting practice for the first time since going on the disabled list Aug. 1. ... RHP Michael Mariot (right hamstring injury) was recalled from Triple-A Omaha and transferred to the 60-day disabled list.
Twins: Rookie RHP Trevor May (0-3) is looking for his first big league victory Friday night at Baltimore. He gave up five runs and 11 hits in 5 1-3 innings in an 8-6 loss to Detroit on Saturday.
Royals: LHP Jason Vargas will start Friday night's series opener against the Indians. He has a 1.24 ERA in his 10 wins and a 6.29 ERA in his six losses.