Blake Treinen has had an eye-opening spring for the Nationals. (David Goldman/Associated Press)

In the Nationals’ clubhouse, Blake Treinen occupies the locker closest to the entrance, in the corner where minor leaguers congregate in early spring. It is a place for extra arms and kids getting their first taste. The players in the row next to Treinen have packed bags and headed to the minor league complex.

The empty stalls symbolize his status at the start of camp. The equipment remaining inside Treinen’s locker symbolizes his revelatory performance. Even he didn’t think he would have a chance to make the team with a week left in spring training. But he does.

“It’s a pleasant surprise,” Treinen said. “My intentions and expectations coming into spring training were just to leave an impression. The fact that I’m still around is an absolute blessing. I’m just trying to make the most of it. Whatever their decision is at the end of spring training is their decision. I feel like I’ve done my absolute best to leave an impression with the big club.”

This afternoon, in the Nationals’ 2-0 loss to the Cardinals, Treinen left another impression. He entered in the eighth inning and faced two batters. Star catcher Yadier Molina grounded out to shortstop, outfield prospect Randal Grichuk struck out looking. Treinen threw his vicious sinker, which hit 98 miles per hour earlier this spring, between 95 and 97 mph.

“Easy 96 with some sink,” Manager Matt Williams said. “He continues to impress.”

“Powerful,” one NL scout texted. “Stuff definitely plays up out of the ‘pen.”

“Excellent!” another NL scout texted. “Good delivery and mound presence.”

I asked the second scout if Treinen was one of the Nationals’ 12 best arms.

“Absolutely!” he texted back. “Kid can pitch on a lot of major league staffs right now.”

Treinen has dazzled the Nationals and the league during spring. His usage suggests they’re considering him in a bullpen role. A starter last year in Class AA Harrisburg, Treinen had been stretched out earlier in camp. Today, the Nationals planned to give him an inning at most. He has relieved in the past, and feels comfortable in the role.

Still, it will not necessarily be easy to put him on the opening day roster. Treinen is not on the 40-man roster, which means the Nationals may have to sacrifice a player – likely either Jhonatan Solano or Jeff Kobernus – in order to put him on the team.

And while Treinen’s arm is undeniably electric, there are questions if his stuff outpaces his results. For such a hard thrower, Treinen has never posted big strikeout totals or a small hit rate. Last year at Harrisburg, he stuck out 6.5 batters and allowed 9.5 hits per nine innings. This spring, Treinen has allowed five earned runs on 15 hits and three walks in 9 2/3 innings.

“He’s still trying to make his stuff play,” the first scout said. “He’s got a great arm, no doubt. But he still doesn’t miss a lot of bats.”

Regardless, the Nationals have buzzed over Treinen’s potential since the start of spring. His presence in the organization is a clear victory. He came over along with A.J. Cole and Ian Krol in the deal that sent Michael Morse to Seattle. Treinen is turning heads, Cole is the Nationals’ No. 2 prospect and Krol became part of the deal that landed Doug Fister.

The trade did wonders for Treinen, too, he said. In 2012, at High-A Stockton of the hitter-friendly California League, Treinen went 7-7 with a 4.37 ERA. Then 23, he felt like he was spinning wheels.

“Coming to this organization is probably the best thing that could have happened to my career,” Treinen said. “Just the whole outlook on pitching and philosophy and throwing program, it’s just taken my career through the roof, more than what I would expect it to be right now.”

The mention of the Nationals’ throwing program seemed particularly interesting. Treinen chose his words carefully and made clear he meant no disrespect to Oakland. With A’s, he never threw more than 120 feet, and coaches instructed him to throw on a line. The Nationals allow more freedom to play long toss.

“You just need to feel your body out,” Treinen said. “It’s allowed me to know my body better than it is a regimented program as opposed to doing what’s best for you. Not that everybody at Oakland did that. For me, it works better here. Something clicked here.”

Treinen has also felt welcomed in his first major league camp. Stephen Strasburg and Craig Stammen have both offered advice.

“Everybody is so willing to help each other,” Treinen said. “I can’t thank the organization – top to bottom, players and stuff – for just being open in every aspect of the game.”

>>> Gio Gonzalez had an uninspiring fourth start of spring. He worked up to 82 pitches, which was the main goal and what matters most. But he allowed two runs (one earned) on four hits and three walks in 4 2/3 innings and did not strike out a batter – which is something that’s never happened to him 153 career regular-season starts. “Didn’t have my best stuff,” Gonzalez said.

Gonzalez has faced the Cardinals a couple times this spring, and  he believes that threw him off a bit.

“It’s been a challenge against a team I’ve faced plenty of times,” Gonzalez said. “A team that’s seen you so many times, your job is just to work on what you can, mix it up as much as possible.”

Williams didn’t buy that.

“Not really,” Williams said. “Not at this point. It’s about his pitch count and him throwing his pitches where he wants to throw them. A little bit of a struggle today with command of his fastball. But other than that, it was good.”

>>> Anthony Rendon did not travel with the Nationals and has been laid low by the chest cold that has been going around the clubhouse. “He may be down a couple days,” Williams said. “He’s been feeling bad.”