The bottom-line reason that the Braves are carrying three catchers on their roster is because one of them, Evan Gattis, is capable of hitting a game-changing home run at any time.

The big rookie with the splendid nickname — El Oso Blanco, aka “the White Bear” — did it again Saturday.

Gattis came off the bench to hit a two-run homer in the eighth inning, lifting the Braves to a 3-1 win against the Los Angeles Dodgers at Turner Field. A crowd of 38,615 roared as Gattis circled the bases, then again when Andrelton Simmons followed with another homer on the next pitch.

“He likes these moments it seems like,” Braves manager Fredi Gonzalez said of Gattis, who is tied for third in the majors with six game-winning RBIs, and leads major league rookies with eight homers and 22 RBIs. “There was nobody in our dugout tonight that wouldn’t want him up in that situation

“He’s the kind of guy who doesn’t really even have to hit the ball square to hit it the ball out of the ballpark, and obviously that’s what we were looking for tonight there, and he gave it to us.”

The 240-pound Texan has two home runs in four major league pinch-hit at-bats, and six of Gattis’ eight homers have given the Braves a lead. He was asked about hitting in game-on-the-line situations.

“I like it,” he said. “It reminds me of winter ball. I haven’t had that many at-bats with that kind of intensity, and I like it.”

Gattis led the Venezuelan League in homers and slugging percentage, and that’s also where he got his nickname.

“He’s awesome,” Simmons said. “Just amazing. Pretty much all you can say. You saw it coming, but still, seeing it is awesome. He’s a great hitter. He’s always ready to go. He’s fun to watch.”

Craig Kimbrel had two strikeouts in the ninth inning for his 13th save, and Cory Gearrin (1-0) pitched a perfect eighth inning for the win after a strong performance by Kris Medlen.

Gattis and Simmons homered off right-hander Kenley Jansen, a fellow Curacao native whom Simmons has known since the shortstop was 4 years old and played on a team with him. Simmons had never faced him before and went on the scouting report from Braves veterans.

“They were talking about his pitches, saying he likes to throw that back-door cutter,” Simmons said. “So I was kind of looking for that, and he threw it first pitch. I’ve got to thank Gat for wearing him out a little bit. Made it easy.”

Gattis sought out Justin Upton before the at-bat, while Jansen warmed up.

“I wanted to make sure it was the right guy, because when he was running in I thought it was what’s-his-name, Bonifacio (Ronald Belisario). And it was it was Jansen. Throws a lot of cutters, and Justin has faced him a lot. I remember him saying something about him in the advance meeting, so I wanted to go and just talk to him and whatever info I could get going into an at-bat is going to help, especially at a time like that.”

The Braves mustered only five hits against Dodgers lefty starter Chris Capuano, who left with a 1-0 lead after B.J. Upton’s one-out single in the eighth. With Gattis entering to pinch-hit, the Dodgers brought in the righty Jansen to face him.

Gattis fouled off three consecutive two-strike pitches before lining the eighth pitch of the at-bat into the left-field seats.

“I fouled off some pitches and got one I could handle,” he said. “Thank God it went out…. The crowd, the intensity and all that, definitely a good feeling. It’s definitely a good moment, man.”

The Braves have won the first two games of the homestand to clinch a series win against the Dodgers, after losing their last two series on a 3-7 trip that ended Wednesday.

Medlen got no decision but had his best start of the season, allowing two hits, three walks and one unearned run in seven innings.

“Medlen was outstanding,” Gonzalez said. “I thought we were going to come in tonight and talk about another day that he didn’t get any run support — and he didn’t, but he still pitched a heck of a ballgame.”

Medlen would be the first to tell you he hasn’t pitched as superbly as he did last season. Others with the Braves will tell you he’s also had lousy luck and pitched a lot better than his record indicates.

He avoided losing what would have been his fifth consecutive decision over his past six starts, but remained 1-5. The Braves provided no offensive support while he was in the game, and an outfield error by Justin Upton let in the only run.

But Medlen was all upbeat afterwards, pleased by his progress and the fact that he threw a season-high 112 pitches and seven solid innings on a night when the Braves’ injury-riddled bullpen needed it.

“I felt awesome,” he said. “At San Francisco (last week) I was leaving the ball up. Today if I missed, I missed down. That was huge for myself. Just tried competing. Obviously Capuano had a great game today. Real tough (outcome) for him, but I think that’s our offense in a nutshell – shutting us out for the entire game. One inning, just waiting for our offense to explode.

Medlen didn’t give up a hit after Skip Schumaker’s two-out, opposite-field double in the fourth inning. Adrian Gonzalez, who had walked with one out, scored from first base when Upton didn’t field Schumaker’s hit cleanly in the left-field corner.

There have been only seven unearned runs against Braves pitchers this season, and five of have gone on Medlen’s ledger. That’s more than 20 percent of his 24 total runs allowed have been unearned.

Meanwhile, his run support dried up a little more. It was already the third-lowest among National League starters before Saturday at 2.75 per nine innings pitched. In Medlen’s eight previous starts, the Braves scored two runs or fewer five times.

They didn’t score until after he left the game Saturday, but with one swing of Gattis’ bat, they scored enough.

“How fitting is it that B.J. got it started?” Medlen said of the slumping center fielder’s eight-inning single. “I think it was awesome for him to get a hit and get on base for us, and you’ve got Gat coming up and you obviously have the faith that he’s going to get it done.

“There was absolutely no doubt in my mind — he definitely wasn’t going to get cheated, but he was going to put some swings on it. He faced a tough pitcher and got the pitch that he wanted, and absolutely crushed it. And Andrelton followed with some breathing room, and Craig did his thing.”