Troy Patton ended up replacing Johnson, but not until the Indians loaded the bases with no outs, tied the game on a fielder's choice grounder and took the lead on another force play.
"I wasn't going to extend Jimmy any more than I had to," Showalter said after a 4-3 loss. "Same reason why Troy came in."
Johnson, standing at his locker after his fifth blown save, ripped himself for the four-pitch leadoff walk to Michael Brantley that started the decisive rally. Showalter was much kinder.
"It's not just Jimmy," Showalter said. "We had a tough time solving (Scott) Kazmir. Jimmy's been solid for us. He's a rock. And he'll be back and pitch and be a part of contributing hopefully to a good club.
"Tonight, he elevated the ball a little bit the first couple hitters and then he pitched real well after that."
Kazmir took a no-hitter into the seventh before Manny Machado's leadoff double.
"He was using what was being given to him and making it work for him," said Showalter, clearly upset with plate umpire Ted Barrett's strike zone. "He's got a good arm, velocity. Showed enough on the inner half and spun the ball enough. He settled in on that fastball away and in and made use of it very effectively. He had a good outing, obviously.
"I thought Ham (Jason Hammel) did, too. We had a chance. Our guys fought their way back. Tough game. A lot of good things, and some things that were challenging. That's the way I look at it.
"I'm impressed with Ham. Got a big out there in the seventh to get off the field. Thought Brian (Matusz) threw the ball pretty well."
Kazmir left the game before throwing a pitch in the eighth, the Indians' head athletic trainer by his side, and Showalter fumed as reliever Joe Smith continued to warm in the bullpen instead of the stadium mound.
"It's just, you have to warm up on the mound, and the umpire was out there telling him to come in, but he kept throwing," Showalter said. "It's just something that's always been a rule. So, it just wasn't being enforced."
The go-ahead run scored on Drew Stubbs' grounder to Machado, who tried for the double play instead of throwing home. Did Machado have a play at the plate?
"I'd have to look at it real closely," Showalter said. "I can't tell you for sure. But you know, I trust our guys' decisions. Manny has been making great decisions. It was close, close. You've got options there and you've got a split second to make a decision. I applaud him for trying to throw, trying to do what he did."