FORT MYERS, Fla. -- On the first day after receiving his work visa from the U.S. government, Rusney Castillo went to work.

There was nothing glamorous about the day for Castillo, a 27-year-old Cuban native who signed a seven-year, $72.5 million contract with the Boston Red Sox, the largest contract ever given to an amateur.

Castillo had two sessions in the batting cage on Thursday morning in Fort Myers. Rick Weber

Under a searing Florida sun on Thursday morning, he was taken through a series of basic drills by Laz Gutierrez, the organization’s coordinator of player development programs, while a dozen fans and autograph seekers watched from behind the fence on Field 3 at the Fenway South complex.

But it was clearly a big day for Castillo, who smiled broadly throughout the workout -- which came less than a day after he found out he had been granted a P-1A work visa from the U.S. Customs and Immigration Services for "internationally recognized athletes."

He is now eligible to play in games, although the Red Sox are keeping a veil of secrecy around their plans for him. Castillo is not being allowed to talk to the media until he plays in his first game, and no one at Fenway South is authorized to talk about Castillo.

Castillo did not play for Boston's rookie league affiliate in the Gulf Coast League in Thursday’s game against the Orioles -- the last regular-season game. The Red Sox, who won the GCL's South Division, play a one-game semifinal Friday, with the winners meeting in a best-of-three final beginning Saturday.

It is expected that Castillo will be brought up to the big leagues before the end of the season, but Red Sox manager John Farrell has said that Castillo probably will play at least a few games in the minor leagues before that happens.

Red Sox fans will have a hard time staying patient. In this devastatingly disappointing season, Castillo provides hope. Nothing can be done to salvage this season, but Castillo is an electrifying light that will brighten the months leading up to spring training.

Father Jerry Hogan, a Boston priest who is staying at his home in Sarasota and will be attending this weekend’s games against the Rays at Tropicana Field, drove down to Fort Myers on Thursday morning to see what the Castillo buzz is all about.

After a few hours on the field and in the cage, Castillo signed autographs for everyone who asked. Rick Weber

“It’s the most exciting thing going right now, especially since we’re in last place,” he said. “He’s a Cuban player, and everybody is looking forward to seeing what he can do. You never know, but absolutely, it’s exciting. This is getting us through the season and into next year.”

Castillo could turn out to be a replica of countrymen Yasiel Puig, Jose Abreu and Yoenis Cespedes. Or he could turn out to be something much less -- a center fielder with speed and an average bat. Not everybody agrees on his future, which is especially hard to gauge because he has not played in any games since 2012, his last season in Serie Nacional, the Cuban professional league.

For now, he’s getting to know the Red Sox, and they’re getting to know him.

Castillo’s day started at 7:30 with a session in the weight room. At 8:31, he emerged from the facility and headed to the cage, where Gutierrez fed him pitches for 27 minutes.

At 9:05, Castillo headed out to Field 3, where he stretched and did some long toss with Gutierrez. At 9:33, he grabbed his glove and headed to center field, fielding fly balls and line drives from Gutierrez, who spoke to him in Spanish throughout most of the workout.

At 9:44, he got into the batting cage and hit for 17 minutes. Castillo has been criticized for a “long swing,” but the ball comes off his bat in explosive fashion. He has added 20 pounds of muscle since defecting from Cuba, but he still appears to be the line-drive hitter he was in Cuba.

After batting practice, Castillo got back in the box and simulated the hitting motion, running to first. After a few minutes, he practiced rounding first and running through second base.

At 10:12, his workout was done, and he started heading for the center field exit with Gutierrez.

“Rusney!” one fan shouted.

Castillo came over to the dugout and signed every item that was placed in his hands. And he kept signing until the last fan left.