Kimbrel was one out away from his 100th career save Tuesday, retiring the first two batters he faced before Reds catcher Devin Mesoraco sent a 3-2 fastball over the fence in right-center field to tie the game at 4.
It was Mesoraco's first homer of the season and the first pinch-hit homer of his career.
Shin-Soo Choo, who homered earlier in the game off Braves starter Kris Medlen, followed with a home run to left-center to win the game. It was the eighth multihomer game and the second walk-off homer of Choo's career.
"It is what it is," Gonzalez said. "At the end of the year, [Kimbrel's] going to have 40-something saves and five blown saves or four blown saves. It just so happens he's getting them right here in a little bunch. No worries."
In his past five appearances, Kimbrel's ERA has risen from 0.00 to 3.38.
"We probably won't [use him] today," Gonzalez said, "but yeah, if we've got a save situation [Thursday], we run him back out there, of course."
Tony Meale is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.