He relieved in only eight games last year for advanced Class A Salem, so it figured pitcher Jake Cosart would be back in Virginia in 2017.

But the Boston Red Sox like Cosart’s arm. Despite his inexperience, he began this season in Portland.

“I was out there, a little confident, happy that I’m in Double-A. But it catches up. Wham,” Cosart said.

Wham is a good way to put Cosart’s debut. It’s not that Cosart was getting hit – he wasn’t because he couldn’t throw a strike.

Cosart, 23, a third-round draft pick in 2014, entered the third Sea Dogs game of the season, tied in the eighth inning.

First batter: four pitches, walk.

Then, after a sacrifice, five more pitches and another walk.

A full count and another walk to load the bases.

The next batter didn’t walk. He was hit by a pitch. One run in.

Full count on the next batter; Cosart issued his fourth walk, and another run. Portland trailed by two and Cosart was pulled from the game.

What happened to the prospect with a 2.05 ERA in Greenville last year, then 1.00 in Salem?

In his first 10 appearances with the Sea Dogs, Cosart walked at least three batters five times.

“There are obviously ups and downs, but the feeling of being lost out there – it was tough,” Cosart said.

Yes, it’s cold in Portland – “I’m not one for excuses but I’m from south Texas,” he said. “I had a real good spring (training), and then I get up here.”

On May 10, Cosart had a 4.82 ERA and a 2.79 WHIP (walks/hits per inning). He was a wreck on the mound and it wasn’t just because of the weather.

“Stuff like getting demoted creeps into your mind,” he said. “Stuff like, ‘Am I letting the team down?’ And just letting yourself down. Didn’t I just really work hard to get here?”

Separately, Sea Dogs pitching coach Kevin Walker, Red Sox pitching coordinator Ralph Treuel and relief pitching instructor Keith Foulke told Cosart the same thing: Trust your talent.

Reliever Jake Cosart has allowed one hit and two walks over his last nine innings as he’s adjusted to Class Double-A. Courtesy of the Portland Sea Dogs

“They said, ‘We know how good your arm is, and how hard you work. Just stick with it,’ ” Cosart said.

“Easier said than done. I’m pretty hard-headed.”

Cosart reached out to his brother, San Diego Padres starter Jarred Cosart, “and he said the same thing: ‘Stick with it.’ ”

Walker saw the potential. For all of Cosart’s horrible numbers, batters were hitting only .152 against him.

“It wasn’t hits. Just walks,” Walker said. “We talked about focusing on one pitch and not letting the situations that happen dictate the next pitch.

“He really worked on slowing the game down. He’s really simplified it.”

In Cosart’s last four outings, he has allowed no runs, one hit, two walks and a hit batter over nine innings, striking out six.

“It took me a while to listen but I stuck through it,” Cosart said.

“I feel comfortable out there. I’m confident. I think the results are starting to show.”

Of course they are.

“It’s all about gaining some confidence and getting on a roll,” Walker said.

“With him, his arm works so fast. He has such a special arm. It’s so easy. He’s deceptive. Good fastball and a good curveball off it.”

The fastball is usually in the mid-90s. The curve is improved and a splitter is being worked on.

Not bad for someone who has been pitching for only four years or so.

Cosart, an outfielder in high school, was switched to pitcher during the fall season of his freshman year at Duke. But that didn’t work out.

“They said I couldn’t play Division I,” said Cosart, who transferred to Seminole College, a two-year school near Orlando, Florida. He struck out 67 in 64 innings. The Red Sox saw potential and drafted him.

After his solid numbers last year, Baseball America included Cosart in its ranking of Red Sox prospects, at No. 16.

“He’s starting to turn the corner and put those numbers up again,” Walker said.

IN PAWTUCKET, Bryce Brentz is on a tear. Through May 19 he was batting .162. Since then he’s on a six-game hitting streak through Monday, batting .450 (9 for 20) with three doubles and two home runs. … Utility player Ryan Court, who was supposed to begin the season in Portland, continued to lead Pawtucket in hitting at .287/.819 OPS.

IN PORTLAND, third baseman Rafael Devers, 20, is batting .288/.859, despite a recent slump (.135 in his last nine games). Trenton Manager Bobby Mitchell, who has seen Devers in four series this season, is impressed. “I really like Devers,” he said. “He’s a good hitter. He’s a good third baseman. He seems to have a great demeanor about him. No panic. He’s young, too. He’s one of the top prospects in this league.”

IN SALEM, third baseman Michael Chavis was named the Carolina League Player of the Week for the second time. Chavis, 21, batted .462 with a 1.231 OPS, including a double and two home runs. For the season he’s hitting .357/1.130, with 12 home runs. … First baseman Jock Ockimey, 21, is batting .309/.922 with seven home runs.

IN GREENVILLE, right-handed reliever Steve Nogosek, a sixth-round draft pick last year out of Oregon, already has 10 saves in 12 chances. He has a 2.30 ERA/1.10 WHIP, and 37 strikeouts and 10 walks in 271/3 innings.