The play occurred in the eighth inning after Iwamura gave chase to a foul ball near the visitors' bullpen. He could not make the play and the ball hit the ground, rebounding up in freak fashion to catch Iwamura square in the eye socket, leaving a small cut and some swelling above the eyelid.
"It's precautionary for about four or five days," Rays manager Joe Maddon said. "It's kind of a bruise on his eye. We're not going to be able to utilize him for about four or five days. I don't think it's going to exceed five days.
"... It's just a bruise. He got hit in a bad spot. It's like when you get a bruise on your arm, except it's in your eye and you need to be a little more watchful, no pun intended."
Due to the nature of the injury, Iwamura is not available to do anything.
"He's pretty much in a cheerleading mode now," Maddon said.
Maddon said he did not know whether Iwamura would accompany the team to Toronto, or if he would join the team in Miami for next weekend's series against the Marlins.
"It's crucial to be precautionary," Iwamura said. "It's my feeling I'd like to play the game today. But I understand what the doctor is explaining."
Asked about he vision, Iwamura smiled and said through his translator, "My eyesight is as good as my batting average."
Which means Iwamura is seeing at a .370 clip right now.
Upton's best position: Watching B.J. Upton play center field Saturday night reaffirms every opinion expressed stating he is a natural center fielder. He makes running down fly balls appear effortless, and he takes good routes to the ball. On the other hand, Upton has played a flawless second base this season.
So what position does the one-time "Rays shortstop of the future" favor? Upton smiled at the question.
"I don't know, man, it doesn't matter," Upton said. "I would say second base now. That turf out there is tough on your legs. Other than that, as far as being comfortable and playing the two, they're about the same."
At one time, Upton wanted only to play shortstop. Now the question is: Will he ever be asked to return to the position? And if so, would he want to return to the position?
"I don't know, we'll see," Upton said. "If the time comes and I need to play it again, I'll play it. Until then, second base is fine. I feel comfortable there. But I think if you put me back at short right now, I think I'd be fine."
Upton said he is having a lot of fun playing this season.
"I think [being in the Major Leagues is] the biggest thing," Upton said. "Getting back to where I used to be. The goal now is to keep it there. I never had doubts. I just knew some things needed to be done and changed."
Maddon is not exactly sure what Upton's ultimate destination will be.
"I think it will be based on need and how we decide to do things over the course of time," Maddon said. "But I think he can do them both. I think he can be a solid All-Star center fielder, or an All-Star second baseman. It's all going to be precipitated by how he hits."
Sign 'em up: The Rays signed the following players from the 2006 First-Year Player Draft: Angel Chapa, RHP, College of Southern Idaho; Kyeong Kang, LF, Chattahoochee Valley CC (Ala.); Robi Estrada, SS, El Camino JC (Calif.); Michael Ross, 2B, NW Mississippi CC; Mark Thomas, C, Young Harris JC (Ga.); and Justin Reynolds, LF, Mt. Hood CC (OR).
The Rays also signed the following fifth-year seniors: Brett Armour, RHP, Mesa State College (CO), Keith Nelson, LHP, Mesa State College (CO), and Jeffrey Carroll, 3B, California State University, Los Angeles.
Up next: The Rays will wrap up their four-game series against the Royals on Monday afternoon in a 3:10 ET contest at Tropicana Field. Right-hander James Shields will start for the Rays and will be opposed by right-hander Gil Meche.
Bill Chastain is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.