A skinny 17-year-old pitcher from Venezuela signed with the Boston Red Sox in July 2008. Like many Latin American players, William Cuevas began his pro career in the Dominican Summer League.

That was in 2009. By 2011, Cuevas was still in the league despite a respectable 3.14 ERA the previous two years.

“It was a little (frustrating),” Cuevas said. “Nothing to do except to keep working hard and show them why you should move up.”

Cuevas finally reached the United States in that 2011 season. In 2012 he made his first All-Star team and, three years later, is an All-Star again.

Cuevas, 24, is one of the six Portland Sea Dogs selected for the Eastern League All-Star Game on Wednesday night at Hadlock Field.

The timing is right for Cuevas, who will become a minor league free agent at the end of the season. He needs to show the Red Sox – or another organization – that he’s a worthy investment.

“Yeah, it’s an important year,” Cuevas said.

And being an All-Star?

“It helps,” he said.

Cuevas is 7-5 on a team that through Wednesday has only 31 wins. His 3.51 ERA ranks 19th in the league, and he’s first among starters in strikeouts per nine innings (8.77).

“He’s been our anchor in terms of a starter,” said Sea Dogs pitching coach Kevin Walker, who also had Cuevas in advanced Class A Salem the previous two seasons.

“He has come a long way with conviction and confidence and trust in himself.”

That confidence has taken some hits, starting with his lengthy stay in the Dominican Summer League. A top prospect may stay one year or less – 17-year-old Anderson Espinoza started only four games this year before being promoted to the Gulf Coast League in Florida. Then again, Espinoza was signed to a $1.4 million contract and has a fastball clocked in the high 90s.

Cuevas didn’t receive a hefty bonus; he was just a kid who showed potential. So he had to prove himself.

“They want to see consistency and that you have a healthy arm that supports a full season in the U.S.,” Cuevas said.

Three games into the 2011 DSL season – with no earned runs, 12 strikeouts and one walk – Cuevas was sent to Florida. He posted a 2.79 ERA in the Gulf Coast League.

In 2012, Cuevas pitched for the short-season Lowell Spinners, making the New York-Penn League All-Star Game. He finished 8-2 with a 1.40 ERA.

Then, after being delayed at the start of his pro career, Cuevas found himself rushed. In 2013, instead of moving to the next level, at Class A Greenville, the Red Sox pushed Cuevas to Salem. The numbers were not so good: 8-9, 5.05 ERA.

“I was excited but it was hard,” Cuevas said. “It was a tough year trying to figure it out and make adjustments.

“So I went back to Salem. I learned by the mistakes I made there.”

In 2014, Cuevas was used as both a starter and reliever in Salem. It was an up-and-down year (2-6, 4.70), but Cuevas was still sent to Portland for the 2015 season.

With his free agency pending, the Red Sox need to know what Cuevas can deliver.

“Pound the zone. That’s the priority,” Cuevas said.

Besides using a fastball in the low 90s, Cuevas has reintroduced a slider to go with his change-up and curveball.

Cuevas, like all the Sea Dogs starters, has not been able to go far into games. His longest outing is 61/3 innings, and he averages just over five innings a start. While he leads the league starters in strikeouts per nine innings, he also is in the top 10 in walks per nine innings (3.6).

So there is improvement to be made. He will enjoy his All-Star experience next week and then go back to the grind. With free agency coming up, Cuevas is auditioning for a job, with the Red Sox or someone else.

“I have to prove that I’m pretty good,” he said. “Keep working hard second half of the season and (earn) another year.”