Butler, once Kansas City's right-handed hitting machine, has had such a tough season that he was dropped from the lineup for the second time this week.
"It's my job to prove I belong in there," Butler said.
This will help -- a 422-foot home run off John Axford that sailed deep to left field and provided the Royals with their fourth straight victory.
The score was 4-4 and Salvador Perez was on base with a single. There were two out, and Butler was sent to bat for the left-handed Raul Ibanez. The Indians countered by bringing in a right-hander, Axford.
Butler busted Axford's second pitch.
"Axford's got a good fastball, and I got 1-0. Coming off the bench, it's hard to lay off that first-pitch slider. You're looking for a fastball," Butler said. "I was seeing it pretty good -- some days you do as a pinch-hitter, some days you don't. It's really weird. It's the toughest thing in sports to do."
Axford also gave up the game-winning hit in the Royals' 14-inning, 2-1 win on Thursday night.
"It was just a bad pitch, really. I just let it stay out over the plate a little too high up. It was supposed to be low and away and didn't end up there, so it ended up in the seats," Axford said.
This was only Butler's fourth homer all season and, uncharacteristically, he took a few extra moments to follow its flight.
"It's one of those things, when you hit them, you don't feel anything because you hit it so good. I definitely did not feel anything on that one," he said. "You've got a lot of emotion going through there, a lot of excitement. I knew when I hit it, I gave us the lead, and we had three outs to go."
Aaron Crow got those three outs in the ninth, surviving a leadoff double by Yan Gomes. Closer Greg Holland was held out because he'd pitched three games in a row.
"Just to be in that situation is a lot of fun, and it's just something, as a pitcher, you want to be in a lot," Crow said.
Butler's home run was the fifth of the game. Perez and Mike Moustakas hit successive homers off Indians starter Josh Tomlin in the second inning for the Royals' first back-to-back blasts since the same two batters connected on April 23 at Cleveland, also in the second inning.
Carlos Santana belted two homers off starter Yordano Ventura, accounting for the Tribe's first three runs. Cleveland's score-tying fourth run came on an error and a pop-fly mixup in the seventh.
Gomes reached base on Moustakas' throwing error and later scored from third on a sacrifice fly in shallow right. The problem was that second baseman Omar Infante and right fielder Lorenzo Cain were both chasing the ball and then shied away, forcing Cain to make a diving catch. That gave Gomes time to tag up and score.
"That's a tough play, man," manager Ned Yost said. "That's kind of right in the middle of both of them."
But in the long run, it didn't matter, because one inning later, Butler took care of things and earned endorsements from his teammates.
"Billy's one of those guys that was born to hit, and he's always going to hit, and you never count guys like that out," Ibanez said. "You know that eventually he's going to get hot and do what he's capable of doing what he normally does."
Perez, who had three hits himself, chimed in as well.
"Billy's a great hitter. For me, Billy's the best hitter on the team," Perez said. "He's maybe had a little struggle this year, but that's going to happen to anybody. I feel so happy that he got the big homer."
The clutch blast prompted memories of Butler's other pinch-hit homer -- on June 17, 2012, in an Interleague game at St. Louis. The Royals were one pitch away from defeat when Butler connected off Jason Motte for a 2-2 tie in the ninth inning of a game the Royals would win, 5-3, in the 15th.
"That one I'll never forget. This one hasn't quite soaked in yet. When you hit one against the Cardinals in the I-70 Series, it's got a lot of emotion, it's got a lot of tradition," Butler said. "I'm sure this one will overtake it, because it's the most recent. That was a big one, both of them are big. In those situations, you never forget them."
Despite the recent benchings, Yost noted that Butler's attitude has remained good, and Butler insisted that he understood his manager's actions.
"He's got a job to do, putting the lineup out there," Butler said. "As of late, the production is definitely not there. Over my whole career, it's there, but this game's about what you've done for me lately."