Alvarez, who reportedly reached agreement on a $115 million, six-year contract, also had a pair of singles for his fifth straight multi-hit game. His 15 home runs are second in the American League behind the Yankees’ Aaron Judge.
Diaz opened the scoring with a two-run homer in the second and added two singles for his first three-hit game of the season.
“It’s always great when I get a chance to be in the lineup and contribute to the team,” Diaz said. “I know the role I have on this team. I try to stay sharp in the cage and see a lot of videos.”
Diaz was in the lineup at third base in place of Alex Bregman, who was given a scheduled day off.
“He got us on the board,” Astros manager Dusty Baker said. “He got three hits tonight. It’s always good when you can give a guy a day off and get a guy a day to play and then he comes through. He had a great game.”
Maldonado and Alvarez each hit two-run homers in the fifth against Brady Singer (2-1), who allowed seven runs on eight hits over five innings.
“Brady’s stuff was really good today,” Royals manager Mike Matheny said. “I know the numbers didn’t look like it, but he had everything that he needed. He made a mental mistake to Diaz, but the other two home runs were pretty good pitches. Anything he got anywhere near the plate, they were finding barrel.”
“I thought the command was good,” he said. “I was attacking the zone and throwing strike. I just made some bad pitches at bad times and they did some damage.”
Kansas City has lost 12 of 14.
Maldonado’s fourth homer was almost caught by Kyle Isbel as it disappeared inches behind the center field wall.
“I know the guy has a good sinker and I saw something up in the strike zone and put a good swing on it,” Maldonado said. “I thought he caught it. I know how hard it is to hit a ball out to center here. I don’t have the Yordan power. It just barely went out.”
Jose Urquidy (5-2) retired 16 of 17 batters after Whit Merrifield led off the first inning with the first of his two singles. Urquidy went six innings, allowing three runs on five hits and one walk, fanning six.
“Urquidy was finding too much of the plate in that one inning,” Baker said. “Sometimes he throws too many strikes. He was finding the heart of the plate and it was time to get him out of there.”
Bobby Witt Jr. hit a three-run homer, a 443-foot drive into the left field fountains with one out in the sixth. Those were Kansas City’s first runs since the seventh inning Tuesday.
“I knew I was missing fastballs in my last at-bat and just wanted to take a nice smooth swing on the next one,” Witt said. “I guess I did and it felt pretty good.”
Witt’s seven home runs lead the Royals.
Royals OF Michael A. Taylor was reinstated from the COVID-19-related injured list; OF Dairon Blanco was designated for assignment. Astros LHP Blake Taylor left the game with left elbow discomfort after throwing six pitches; he’ll return to Houston for further examination.
Kansas City acquired RHP Albert Abreu from the Texas Rangers for RHP pitcher Yohanse Morel, who was with Class A Quad Cities; LHP Foster Griffin was optioned to Triple-A Omaha.