Tyler Clippard after allowing a game-tying home run to Justin Upton in the eighth inning on Friday. (AP Photo/David Goldman)

Tyler Clippard has been an invaluable part of the Nationals bullpen for the past five seasons. No reliever in baseball logged more work — 323 innings — in the four seasons between 2010 and 2013 than Clippard. In a position of so much volatility, Clippard has been one of the most consistent and effective relievers in the sport. But since beginning of the 2013 season, the Atlanta Braves have been a thorn in Clippard’s side.

Last season, Clippard faced the Braves six times and allowed at least one run in each appearance. So far this season, he has faced Atlanta three times and given up a run in two games. Clippard has appeared in seven games this season and has lost three ties and one lead, including serving up the game-tying home run to Justin Upton in the eighth inning in Friday’s 7-6 walkoff loss in 10 innings. Two of those four game-changing appearances have been against the Braves.

“I don’t know,” he said. “Yeah, they know me. They know me well. But I think it just comes down to I haven’t really executed the way I needed to against these guys in particular. There’s no real rhyme or reason, it’s just kind of coincidental, I think. It’s just one of those things.”

Over his career, Clippard has been great against Atlanta; he has a career 2.87 ERA in 47 innings. In 2012, Clippard faced the Braves nine times and allowed a run in only one appearance. But since the beginning of last season — when the Braves became more of a fly ball and home run-hitting team with the additions of the Upton brothers and Evan Gattis — Clippard has a 9.72 ERA against the Braves.

Clippard is a strikeout and flyball pitcher. He thrives on deception and the high fastball coupled with his disappearing change-up. The occasional home run is an understood byproduct of his style of pitching. The Braves are a challenging opponent for that reason.

Clippard had the second highest flyball rate among relievers last season at 55.8 percent. The Braves were eighth last year with a 35.7 percent flyball rate. Clippard’s homer-to-flyball ratio was average (9.4 percent) but the Braves were second best in baseball (12.6 percent). Four of the Braves returning hitters from last season were noticeably above the average flyball rate: Dan Uggla (47.1 percent), Gattis (44.6 percent), Andrelton Simmons (39.1 percent) and Justin Upton (37.8 percent).

“Obviously the results aren’t there but I feel good,” Clippard said. “I’m making good pitches and the occasional home run, unfortunately, is kind of part of who I am. These outings I’ve been in this year – tie games, one-run games – a few walks here and there have hurt me, but overall, it hasn’t been that far off. Just trying to stay the course and basically stick to my game and the results will come. I’m not worried about that, it’s just frustrating, especially against these guys and the games that we’ve been in to not get the results.”

Against Upton on Friday, Clippard entered with a 6-5 lead. He got Chris Johnson to pop out to second base. Then with a 1-2 count on Upton, he fired a 93 mile per hour fastball over the middle. He wanted to throw it high but caught too much of the plate. As soon as Upton swung, Clippard yelled and clenched his fists. After the game, he sat at his locker, ice wrapped around his arm like normal, but staring at nothing.

“He’s our guy,” Manager Matt Williams said. “We’re going to put him in there. Every pitcher goes through stretches during the course of a season. I’m confident. He’s confident. And he’s the guy that we’ll go to.”