The 25-year-old third baseman, the No. 2 choice in the 2005 draft, batted .198 and committed five errors in 29 games this season. He was sent to Triple-A Omaha to make room for reliever Kyle Farnsworth, who was activated from the disabled list after missing 48 games with a groin strain.
Considered a cornerstone of the last-place team's rebuilding plans, Gordon missed three months after undergoing surgery April 17 to repair torn cartilage in his right hip. He batted .227 in 22 games since returning July 17.
"We moved Alex and decided to give him an opportunity to put some joy back in the game," Royals manager Trey Hillman said before Tuesday night's game against the Chicago White Sox.
"He's just fighting himself. The hip is feeling good but we felt like for at least a couple-of-week period, let him get down there and take a little pressure off," he said. "He's got a lot of things going on right now. He's kind of [struggling] defensively. He's doing some productive things swing-wise, but ... there's a lot going on in his mind right now."
As a rookie in 2007, Gordon got off to a slow start before batting .285 with 12 homers and 52 RBIs in his final 98 games. Last season, he batted .260 with 16 homers and 59 RBIs, finishing third among AL third basemen with a .352 on-base percentage.
"There is some muscle memory, both offensively and defensively, that has to come back," Hillman said. "I think sometimes if you can relieve the stress of the situation, those things have a tendency to come back a lot quicker.
"He's trying to make up for lost time and the injury. Hopefully, he'll come back up in September and do some good things and finish up strong."
Gordon left Chicago for Kansas City earlier in the day and was to join the Omaha team in Tacoma later this week.
Hillman wasn't sure whether Gordon would play two out of every three games at Triple-A, as he had been doing for the Royals since coming off the DL.
"They'll gauge it the same way we did here with how he's feeling physically," Hillman said. "He'll tell you he's able to play every game. He's going to have some days off."
The manager said utilityman Mark Teahen would be Kansas City's primary third baseman until Gordon returns.
Farnsworth was surprised when told he had replaced Gordon on the roster.
"It's none of my business what they do," he said, "but that's obviously probably a shock to a lot of people."