Right-handers Jake Johansen and Austin Voth, the Nationals‘ second- and fifth-round draft picks in June, have adjusted nicely to professional baseball at short-season Class A Auburn.

Johansen, a 22-year-old from Dallas Baptist who signed for $820,000, consistently throws his fastball in the mid-to-upper 90s and has improved the break on his curveball while mixing in eight to 12 change-ups a game. He’s 1-1 with a 1.11 ERA with 30 strikeouts and 15 walks in 32 1/3 innings.

At 6 feet 6 and 235 pounds, Johansen’s focus is on progressing as a pitcher. Dirt biking is listed as a hobby in his Dallas Baptist biography, but he says he hasn’t been on a dirt bike since the fall of his freshman year of college and that his parents sold those wheels long ago.

“He has that special fastball that you hear so much about, and it has a heavy sink to it,” Auburn pitching coach Sam Narron said in a telephone interview. “He also has a curveball that he’s starting to throw with conviction. When he got here, he was babying it a little, but it’s really coming around. His change has some nice sinking action, too.”

Voth (which sounds like both), a 21-year-old from Washington who was third in the Pacific-12 in strikeouts this year and signed for $272,800, has 21 strikeouts and one walk in 19 innings for the Doubledays. He’s 0-0 with a 1.42 ERA after pitching five scoreless innings in the Rookie-level Gulf Coast League. When he was drafted, the 6-foot-1, 190-pound Voth had a fastball that normally hit about 91 mph.

Voth’s “fastball has been improving,” Narron said. “It was already good when he got here, but he has ticked it up a bit. He can run it up to 94 or 95.”

During their first tastes of the minors, Voth and Johansen are making the most of the daily grind in the New York-Penn League, where the Doubledays have struggled with the worst record.

“I’ve learned a lot,” Voth said. “The environment is a lot better for that. In college, so much is about winning that next game, but here it’s all about improving yourself. I’ve been working on how to start off hitters, how to see their stance and react to that.”

Johansen, meanwhile, has enjoyed the transition to being able to pitch inside and low in the zone against hitters with wood bats.

“I’ve been very pleased with everything overall as a whole,” Johansen said. “I’m definitely enjoying the process. I think the Nationals organization has a lot to offer with my mentality and my approach.”

Johansen is developing a harder curveball that he has been throwing at 80-82 mph instead of the 76-79 he did in college. “That has helped my fastball even more,” he said.

As for the dirt biking, he said, “I’m not doing anything crazy like that. That was put on there when I was a freshman and I just didn’t change it. I’m sure there’s something in my contract in the fine print that says I can’t do that, but I’m also sure they trust me enough to know I’m just worried about pitching.”

MORE AUBURN PITCHING NOTES: The Doubledays (16-33) could get a boost from another high pick, as fourth-rounder Nick Pivetta has been promoted from the GCL, where he was 1-0 with a 2.13 ERA in 12 2/3 innings. The 20-year-old right-hander signed for $364,300 out of New Mexico Junior College. …

Left-hander David Napoli, an eighth-round pick from Tulane who signed for $15,000 as a college senior, will represent Auburn at Tuesday’s league all-star game in Norwich, Conn. He’s 1-0 with a 1.37 ERA in 19 2/3 innings of relief. …

Left-hander Kylin Turnbull, who slipped from advanced Class A Potomac to Class A Hagerstown to Auburn, is 2-0 with a 1.96 ERA over his past four starts with Hagerstown after tweaking his mechanics with the Doubledays. “He kind of got his confidence back,” Narron said of Turnbull, who received a $325,000 bonus as a fourth-round pick in 2011. “He was very good for us, and I would love to see him continue to improve and move up the ladder because he’s got good stuff and he’s left-handed.”

GCL JUGGERNAUT: When 2012 first-round pick Lucas Giolito earned his first professional win Wednesday with a five-inning start, his team improved to 35-6. At .854, the Gulf Coast League Nationals have the best record in minor league baseball and had reduced their magic number to win the Eastern Division to three. The second-place Cardinals started Thursday 17 1/2 games behind.