The Boston Red Sox signed Cuban outfielder Rusney Castillo on Saturday and he was on the field at Fenway Park before their game against the Seattle Mariners.

The club is expected to make a formal announcement of Castillo's signing after Saturday's game.

Castillo was seen on the field speaking with Mariners second baseman Robinson Cano. Both are affiliated with agency Roc Nation Sports.

The Red Sox signed Castillo to a seven-year deal worth $72.5 million. According to ESPN.com, he will earn $100,000 for the rest of this season; a base salary of $10.5 million in 2015-17; $11 million in 2018-19; and $13.5 million in 2020. He also gets a $5.4 million signing bonus.

The $72.5 million terms are a record number for a free-agent amateur.

"He's going through the final stages of a full exam here," manager John Farrell said. "There's still a number of administrative things that he's got to go through -- work visa, all that type of things. As far as a timeline, that'll be determined a little bit later."

The club hopes to get Castillo some at-bats with one of their minor league affiliates before he joins the big league club this season.

"I did get a chance to sit with him and talk with him this morning," Farrell said. "He's excited to be here. Glad the process has moved along to this point and excited to get started when that day comes. There's still some things he's got to work through."

Farrell said Castillo's body type reminds him of Los Angeles Dodgers outfielder Yasiel Puig, another Cuban star.

"He's obviously a very strong-looking athlete. Maybe a little bit shorter version of (Puig)" Farrell said. "You get a similar proportion to that type of body. What that means performance-wise, we'll see. We're confident in the athleticism and the overall strength."