"I was starting to feel real good at the plate when I went down there," Diaz said.
After rejoining Omaha, Diaz was 10-for-32 (.313). His overall average was .345 with six homers, a triple, six doubles and 22 RBIs.
The Royals needed another hitter because first basemen Mike Sweeney and Ken Harvey and outfielder Eli Marrero are banged up.
Sweeney has a sore right oblique muscle in his rib cage and probably won't be in the starting lineup until Tuesday. Harvey aggravated a lower back strain in Friday night's game. Marrero, who filled in at first base, twisted an ankle chasing a blooper Friday night.
Bautista went on the 15-day disabled list with tendinitis in his right shoulder.
"We don't think it's anything serious, but with a young pitcher, we're going to be cautious," interim manager Bob Schaefer said. "We don't know if he's been favoring it lately or what the deal is, but he has a good arm and he's going to be a good pitcher someday."
The Royals have an open date Monday, so they'll merely skip Bautista's turn and start Jose Lima instead Tuesday night against the Baltimore Orioles. They won't need a fifth starter until next Saturday night against the St. Louis Cardinals.
"We have a few days to think about that one," Schaefer said.
That starter will not be Mike Wood, a right-hander that Schaefer believes is more valuable in the bullpen.
"He started last year, but I like Wood late in the game because he can throw strikes, get a ground ball, can field his position and can hold runners on," Schaefer said.
Graffanino at first: With Sweeney, Harvey and Marrero out, the Royals turned to utility infielder Tony Graffanino at first base Saturday night. He hadn't played since last Sunday when he jammed his right wrist in a collision with Orioles first baseman Chris Gomez.
"Graf is our best first baseman right now," Schaefer said. "He's played first before, but I told him he's got 3 1/2 hours to learn how to play it."
Graffanino has played first base just six times in the Majors and this was his first starting assignment.
Outfielder Matt Stairs has 167 games at first base in his career, but Schaefer used him as the designated hitter.
"I want to keep Stairs as DH because he ran around the bases twice the other night, like 90-yard dashes from first to home, and I don't want to kill him in the outfield either," Schaefer said with a grin.
Graffanino also took over Sweeney's third spot in the batting order.
"He's like another top-of-the-order guy. We've got three No. 1 and No. 2 hitters and we've got a bunch of guys together who can get on base. We don't have a true No. 3 hitter with Sweeney out of the lineup," Schaefer said.
"I think with Graf batting third, it just gives us another chance to have a guy on base with Stairs coming up."
Royals trivia: On May 14, 1977, a pitcher recorded a significant first at Kauffman Stadium. What was it? (Answer below.)
Farm report: First baseman Justin Huber's two hits in Double-A Wichita's 7-5 win over Springfield, Mo., on Friday raised his average to .397.
Omaha got home runs from Aaron Guiel, Adrian Brown and Jaime Jones in a 10-5 loss at Salt Lake. Starter Dennis Tankersley gave up six runs in just 1 2/3 innings; he's 1-4 with an 8.14 ERA.
Chris Lubanski hit his fifth home run and Mitch Maier had his California League-leading 18th double in Class A High Desert's 7-5 win over Lancaster. ... Luis Cota struck out 10 and allowed only two hits in six innings as Class A Burlington beat Lansing, 3-0. Yovany Damico pitched three hitless innings to finish up.
Foul ball scare: The boy struck by a foul ball at the Devil Rays-Royals game Thursday night was released Saturday from a local hospital.
Adam Lechner, 9, incurred a fractured skull and blood on the brain after being hit by a foul ball off the bat of Rays catcher Toby Hall on Thursday, but improved to stable condition Friday before his Saturday release.
The Rays sent a signed bat to Lechner's hospital room on Thursday and Hall had planned to visit the boy Sunday morning. Though Lechner has been released, Hall said he still plans to call the boy.
Royals pitcher Jose Lima, who threw the ball that ultimately hit Lechner also said he planned to send the boy a jersey.
Trivia answer: Jim Colborn became the first Royal to pitch a no-hitter at Kauffman (then Royals) Stadium. He beat the Texas Rangers, 6-0, facing just 28 batters. He hit Toby Harrah with a pitch and walked Jim Sundberg.
On deck: The Royals and the Devil Rays will wrap up their four-game series at 1:10 p.m. CT Sunday at Kauffman Stadium. Royals right-hander Zack Greinke is matched against left-hander Mark Hendrickson.