"More than anything, it will help establish a little more regular of a routine. But honestly, that didn't affect me all that much last year," said Castillo. "It will just come down to commitment and discipline this year. But it will be nice to start to establish a more regular routine."
Castillo is getting ready to spend 2015 with just the Red Sox, and he could be the starting center fielder on Opening Day. To prepare for that, Castillo has spent this week participating in the club's Rookie Program with nine other players.
"Rusney definitely has one of the bigger challenges, just due to the cultural change and the level and getting to know the organization and staff and players -- there's a lot to it," said director of player development Ben Crockett. "He's had a bit of a whirlwind tour, playing for four different teams last year in-season, and then getting a chance to play in the Fall League and getting exposed to more American baseball and the cultural stuff of living in Phoenix. And then on the baseball side in Puerto Rico."
It's still hard to know exactly what kind of player Castillo will be in the Major Leagues, because his development hasn't been as charted as a typical prospect.
But the Red Sox are encouraged by what they've seen at every step, including this week's Rookie Program.
"He's been tremendous. He's really focused in everything he does. He has a tremendous routine that starts in the cage every day," said Crockett. "He's got a tremendous workout routine that he's been really dedicated to, and at the same time he's wanted to learn, he's asked a lot of questions, he wants to take in the things that he can from what we're doing and implement those into his routine. Despite all that movement, despite all that change that he's had, he's been able to stay focused on playing."
Castillo's adjustment remains two-fold for now -- culture and baseball.
"So far, so good," Castillo said. "Everywhere I go, I always try to learn something new and adapt to a new place -- whether it be culturally or the weather being in Miami and being in Boston. I think it's gone pretty well."
Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.