BOSTON — The Red Sox signed outfielder Rusney Castillo exactly one year ago Sunday. His major league ceiling and his long-term impact with the organization remain a mystery.

But while Castillo has looked like a bust almost as often as he’s looked like a potential All-Star, the Red Sox should feel good about the direction the Cuban outfielder is headed. Castillo’s most recent call-up has yielded solid results and continued adjustments. He should hit the ground running in 2016.

“Right now, he’s at the top of his game that we have seen,” acting Red Sox manager Torey Lovullo said before Saturday’s game against the Kansas City Royals at Fenway Park. “Is it his peak? Not by any means. I think he’s got a long way to go, and he’s going to get there, because he’s a kid that has great aptitude, there’s a little bit of a language barrier that is decreasing and he pays attention and he cares.

“I think he represents a lot of the things that we want as a Boston Red Sox and he’s going to continue to improve through my eyes.”

Castillo, who defected from Cuba in late 2013, flashed his potential in 10 major league games down the stretch last season after signing a seven-year, $72.5 million contract with Boston. He slugged two home runs, drove in six runs, swiped three bases and posted a .928 OPS in 40 plate appearances.

But injuries, including an oblique issue in spring training, proved problematic. He ultimately joined Triple-A Pawtucket to begin the 2015 season — Boston’s crowded outfield and Castillo’s minor league options also played a role — and he looked overmatched after finally joining the Red Sox in late May, leading to a demotion that seemed to serve him well. The 28-year-old has been a different player since returning to the Red Sox in late July after Boston traded right fielder Shane Victorino.

“Came to us very raw, almost kind of like a tryout camp potential. He was strong, he was physical, but he had to get back into the baseball shape that you see today,” Lovullo said Saturday. “It took a little bit of time last year, the swing’s starting to shorten up, he’s starting to catch up to some live pitching and that takes time.”

That understanding that Castillo was — and still is — far from a finished product explains why the Red Sox have shown such patience with the outfielder. Not every international player is going to burst onto the scene like Jose Abreu or Yasiel Puig. While Castillo isn’t that young — he turned 28 in July — there’s definitely room for growth. And that growth — on display of late — should continue as Castillo adapts to new cultural norms and learns the idiosyncrasies of baseball in the United States.

When Castillo starts to “figure things out” — for lack of a better way to put it — in his new environment, the Red Sox could have a very good player stationed in right field (or wherever) for the foreseeable future. He obviously has a dynamic skill set and a knack for impacting the game in multiple ways.

“Those are little things, little instinctual plays that you can’t practice and you can’t quite work through unless it happens,” Lovullo said Saturday while discussing a heads-up baserunning play Castillo made Friday night against the Royals. “He has this great athletic ability and these instincts to match, and we want him to be fearless out there. But be fearless and be smart, and that was one of those moments.”

Castillo is hitting .342 with a .377 on-base percentage and a .548 slugging percentage since being recalled from Pawtucket on July 27. There still will be growing pains — his mental lapse this week being Exhibit A — but the pros of having Castillo far outweigh the cons of his lucrative deal one year later.

Thumbnail photo via Winslow Townson/USA TODAY Sports Images