Julio Teheran. (Photo by Norm Hall/Getty Images)

The Nationals will face the stiffest test of their four-game series against the Braves on Saturday when they step into the batter’s box against starter Julio Teheran. The right-hander has become one of the best young pitchers in baseball, and among the best in the National League, with his dominant start this season.

Through 15 starts, Teheran is 6-4 with a 2.31 ERA over 105 innings. His ERA ranks sixth in the majors but his WHIP (0.93) is tied for second among all qualified starters. The Colombian native doesn’t walk many batters and gives up few hits (a stellar 6.6 hits per nine innings). Just as impressive, he averages only 13.9 pitches an inning, better than all but two starters (Tim Hudson and Henderson Alvarez). Since joining the Braves’ rotation in 2013, Teheran’s 2.88 ERA is the 11th best in baseball.

“The experience has helped a lot,” he said earlier this week. “I’ve grown more comfortable with my team and the league. I’ve been motivated, too. I’m pumped about how I’ve been throwing and I keep working to get better.”

FanGraphs.com calculates pitch values and Teheran’s fastball, curveball and change-up rank highly. Teheran’s four-season fastball has saved 3.7 more runs than average, good for the 22nd best four-seam fastball in baseball. His two-seam fastball has saved 4.3 more runs than average, the 13th-best mark in the majors. His curveball has saved 3.4 runs (11th) and his change-up is 5.8 runs (11th) better than average. Teheran also added a slider for the 2013 season, along with his change-up. How many starters have four standout pitches plus an improving slider?

“He’s got a really good slider and people are starting to know that,” catcher Gerald Laird said. “He’s got that swing-and-miss slider that’s hard to teach. The main thing is he’s starting to pitch. He’s using his fastball to get to his slider and not using it as much. For him, he’s throwing all four pitches. … For the most part, this guy has been one of the best pitchers in baseball because of the command he has and then that swing and miss slider.”

Over the past two season, Teheran has had success against the Nationals. Among current Braves starters, he has the best ERA (2.93 over seven career starts) and a 3-1 record. He neutralized many of the Nationals’ best hitters: Ryan Zimmerman is 2 for 14; Anthony Rendon is 1 for 9 and Jayson Werth is 3 for 16. Adam LaRoche has had success; he is 5 for 14, Also, Ian Desmond is 7 for 20 and Denard Span is 7 for 22.

“Because we’re from the same division and we face each other often, the faces are more familiar,” Teheran said. “I know how to throw to each of them more or less. But sometimes that’s an advantage for them, too, because they see me a lot. I try to do something a little different each time so it’s not the same.”