Left-hander Hoby Milner was optioned to Durham to make room for Williams.
Williams, 22, made his debut when he pinch-hit for Adeiny Hechavarria in the seventh inning.
"It was crazy," Williams said. "I wasn't nervous after the first pitch. My mind was saying, 'Just try to get the job done.'"
Williams was used as a pinch-hitter because Hechavarria left the game with an oblique issue. So the left-handed hitting Williams' first at-bat came against left-hander Adam Conley.
Williams then hit into an inning-ending double play.
"I do a lot of dumb things, but I don't know if I'd go left against left," said Rays manager Kevin Cash, when asked about Williams getting put into a tough spot. "It was probably good, because we ambushed him. ... He didn't have time to think about it."
Williams was hitting .267 with eight home runs and 45 RBIs in 87 games for the Bulls this season.
"Exciting young player," Cash said. "Talking to [Durham manager] Jared [Sandberg] today, he's made progress. Obviously, any guy at Triple-A, there's still room to improve. He's done some good things. I know our hitting coordinators and hitting coaches, they really like him. He hits the ball really hard.
"I saw him in Spring Training, and then I saw him out in the Arizona Fall League. A lot of talent. He's young, but hopefully we can get him out there, get him in a ballgame, and let him get acclimated like we've done with a lot of these other guys."
Cash said he did not know if Williams' time with the club will be an abbreviated stint or not.
"In fairness, a lot will be determined by [Kiermaier] and how he's able to respond and come back from his foot injury," Cash said.
Durham was in Buffalo, so Williams did not make it to Tropicana Field in time for the start of the game.
Williams was selected by the D-backs in the second round of the 2013 Draft and was acquired by the Rays in the November 2014 trade involving Jeremy Hellickson.
Cash noted that Milner's performance Friday night -- when he allowed three runs (one earned) in two-thirds of an inning -- had nothing to do with the move. They simply needed another position player.
"You hate doing that," said Cash about optioning Milner. "We're intrigued by Hoby. We like Hoby. The deception he creates, [it's good for] left on left matchups."
Kiermaier day to day
A day after leaving the game with right foot pain, Kiermaier had an MRI and got a cortisone shot.
"There's still a bone bruise there, just kind of like we expected," Kiermaier said. "So I got a cortisone shot, so I should be feeling 100 percent by Monday."
Kiermaier told reporters that the lingering pain in his foot stems from an April 8 game in which he fouled a ball off his foot.
"Yesterday was kind of the breaking point for me and the worst day I've had, so I had to speak up and let these guys know that we need to do something else to figure this thing out," said Kiermaier, who hit a leadoff double Friday night but had to leave the game after the fifth inning.
Kiermaier will have to wait 36 hours after the shot before he can resume activity.
"I'm happy that I'll feel as good as I've felt all season, once Monday comes around," Kiermaier said.
"We're going to give him a day or two to kind of see if that pain and irritation subsides and we'll go from there," Cash said. "But we're hopeful that he'll be in here real soon for us. We didn't place him on the DL, so we think he'll be back sooner than later."
Bill Chastain has covered the Rays for MLB.com since 2005.