Luxury tax threshold blocking Rusney Castillo's return to the big leagues.

FORT MYERS, Fla. – Officially, Rusney Castillo’s baseball address this season will be Pawtucket.

In practical terms, ‘’limbo’’ will be more like it.

Castillo could be on pace to win the Triple Crown in the International League, and it’s unlikely that will earn a promotion back to the majors.

The reason: the competitive balance tax (CBT) threshold.

Assuming that the Sox officially announce the J.D. Martinez signing one of these days, his addition to the roster will put the Red  Sox at around $232 million in salaries and benefits for the 2018 season. Already well over the initial CBT threshold of $197 million, the Red Sox risk additional penalties if they go over $237 million, including a 10-spot drop in the 2019 draft and the forfeiture of $500,000 in international pool money.

Beginning in 2016, when the Sox outrighted him off the 40-man roster, Castillo’s annual salary ($11 million for both 2018 and 2019 before jumping to $13.5 for 2020) has not counted as part of the major league payroll. If he returns to the 40-man roster, the Sox payroll will zoom past the next threshold and penalties will be incurred.

Surely, the Red Sox are not about to incur those penalties to have Castillo be fifth outfielder.

In many ways, Castillo earned a spot in the big leagues through his play at Triple A last year. In 87 games, he posted an .857 OPS with 15 homers and a slugging percentage of .507. A strong season in winter ball, including a home run in the championship game of the Caribbean Series for Puerto Rico, followed. It was the kind of level of play the Sox expected when they outbid others to sign Castillo, rather than the unimpressive seasons he put up in 2015 and 2016.

Instead, Castillo is effectively blocked from making it back to Boston – at least for this year – because of the seven-year, $72.5 million contract he signed when he left Cuba in August of 2014.

“I honestly don’t think about it,’’ said Castillo through a translator. “I try to keep it out of my mind. What I’m looking for is success, at whatever level that I’m at and I want to work hard to get that success. Luckily, last year at Triple A, things went really well for me and I’m just going to keep doing the same thing and get some success wherever I’m at.’’

It would behoove Castillo to be traded to another organization, one not currently bumping up against the luxury tax threshold. For that to happen, the Sox would probably have to either take back much of the remaining money ($35.5 million over  the next three years) or, agree to take back a similar sized contract.

Could he envision a time when he might request a trade elsewhere?

“Possibly,’’ he said. “If I were on another team, that wouldn’t be that luxury tax stopping me from playing. But again, I try not to think about it and I try to stick to my goal, which is to be in the big leagues. I want to be in the big leagues, playing (all the time), the way I was in 2015, being up here the entire season. That’s what I try to focus on.’’

All the while, playing in limbo.