Rays starter Matt Moore (0-2) came out in the fifth inning with a sore left elbow. The All-Star lefty grimaced after throwing a pitch to Norichika Aoki and was immediately removed by manager Joe Maddon.
Moore won 17 games last year, but missed 31 games with an elbow injury. He threw 78 pitches Monday and was replaced by Cesar Ramos.
"It has to be checked," Maddon said. "There will be tests tomorrow. We don't know what's going on yet. We'll get an update later. He tried to talk me out of taking him out but I said I didn't think it's a good idea. I went out there and I wanted to give him the benefit of the doubt. I like to communicate with our guys. He just felt something on a pitch. We knew we can't take any chances on anything."
Moore said his final pitch was a changeup.
"There was no particular pain," he said. "It really came out of nowhere. I felt it when I was pitching to Escobar, on a changeup, and then I threw two more changeups to Aoki and I felt it. I actually threw a curveball to Aoki to see if I would feel it then, too, but I didn't. It may have something to do with changeups in that situation."
Moore, who will have an MRI exam Tuesday, went on the disabled list last July 31 with a sore elbow and did not return until Sept. 3.
"It's the same pitch and the area is pretty much the exact same spot," Moore said.
Infante was spitting blood as trainers held a towel to his face.
"They put a number of stitches in there to close the cut," Royals manager Ned Yost said. "They are going to go scan it and see if his jaw is fractured. We'll know more later. I'm not going to make any decisions (on roster moves) until we find out what's going on with Omar and we'll move forward from there.
"He was bleeding tremendously from the cut. I didn't know until they had taken him upstairs that he got hit on the jaw. When we got there they had the towel (over his head) and there was blood all down his shirt. There was no cut on his forehead that I could see."
Danny Valencia ran for Infante, who signed a $30.25 million, four-year contract with the Royals in December after hitting .318 last season for Detroit.
"He was smoked. We're worried about a concussion, too. It shakes you for sure because it's a very ugly sound for somebody to be hit in the face," Yost said. "It was a cool night, but I noticed I broke out in a sweat real quick, so it definitely affected me. Of course, you have a lot of worry about it."
Vargas (1-0) allowed four hits, walked one and struck out two in eight-plus innings, lowering his ERA to 1.20 in two starts. He lost his shutout bid when Ben Zobrist homered on his second pitch in the ninth.
Escobar was 1 for 19 before his bases-loaded double off the left field wall on a 2-2 pitch from Bell with two outs in the seventh. Escobar's three RBIs matched his career high. Alex Gordon, Salvador Perez and Lorenzo Cain singled to load the bases before Escobar's first extra-base hit of the season.
Eric Hosmer singled home Aoki, who tripled, in the first inning.
The Rays, who have lost seven straight at Kauffman Stadium, have scored three runs in their four losses this year while going 2 for 33 with runners in scoring position during those defeats.
Evan Longoria had three of the Rays' six hits.
The Royals placed LHPs Tim Collins (strained left elbow) and Francisley Bueno (sprained left little finger) on the disabled list. They recalled RHP Michael Mariot and LHP Donnie Joseph from Triple-A Omaha. ... The Rays are 3-14 in road openers. They have not won a road opener since 2010 at Baltimore. ... Royals RHP Louis Coleman (bruised right middle finger) threw a bullpen session and could be activated Tuesday, the first day he is eligible to come off the disabled list.