After winning the rights to sign Cuban-born prospect Rusney Castillo, the Boston Red Sox introduced the newest member of the organization Saturday night at Fenway Park.

Following the Red Sox's 7-3 loss to the Seattle Mariners, which extended Boston's losing skid to seven straight, general manager Ben Cherington introduced a player the organization hopes will be its future center fielder.

The sides Friday agreed on a seven-year, $72.5 million deal, and Castillo passed his physical on Saturday before he officially signed his contract. Dressed in a sharp gray suit with a purple shirt and purple and gray tie, Castillo put on a No. 38 Red Sox jersey and donned a Red Sox hat for the first time.

The deal begins in 2014 and continues through '20. Castillo, who will earn $100,000 for the remainder of 2014, will receive a base salary of $10.5 million in 2015-17, $11 million in 2018-19, and $13.5 million in 2020, a league source told ESPNBoston.com's Gordon Edes. Castillo also gets a $5.4 million signing bonus.

The contract also includes an opt-out to become a free agent after 2019 (which will be Castillo's age-31 season), according to ESPN's Pedro Gomez. This is the first time a Cuban player is guaranteed the right to, at some point, give up guaranteed money for free agency.

"It really means a lot for me to be able to be a part of such an historic organization and I'm ecstatic to be here," Castillo said, with the help of translator Adrian Lorenzo.

Castillo will return to Miami on Saturday night and still needs to secure a work visa. Once that issue is cleared, he will travel to the Red Sox's spring training facility in Fort Myers, Florida, and in the next few days will continue his baseball activities, with the hope he can ramp up his game preparation and play in a few minor league games before that season is over next week. The overall plan is to have him play for the Red Sox in September.