It’s been well documented how many prospects the Portland Sea Dogs lost on their way to a franchise-best record of 88-54 this season.

Wednesday, the Sea Dogs begin the first round of the Eastern League playoffs in Binghamton, New York, in a best-of-five series against the Mets. This time around, the Boston Red Sox have added high-profile talent to the Portland roster, assigning Cuban outfielder Rusney Castillo to the Sea Dogs.

Castillo, 27, signed a $72.5 million deal in August that covers the rest of this season and then six more years. He played two games in the rookie Gulf Coast League, which ended Monday. The Red Sox desperately want to get Castillo more playing time and picked the Double-A level for his next stop.

The move has similarities to 2006 when Boston obtained minor league catcher George Kottaras from San Diego at the end of August, in a deal for pitcher David Wells. Kottaras was sent to the Sea Dogs, and he helped them in their Eastern League championship run that year.

The move is obviously different because Kottaras was a low-level prospect who would go on to be a backup catcher for one season in Boston.

The Red Sox have higher hopes for Castillo.

Boston fans hope to see a glimpse of his potential this week.

Sea Dogs fans hope he can help Portland to a title.

He’s a star player with a lot of pressure on him, but Castillo’s transition to the Sea Dogs should be seamless.

“We’ve got some good chemistry here so it should be an easy clubhouse to step into,” said catcher Michael Brenly.

Brenly, 27, is one of the clubhouse leaders. He’s been on a title team before (Florida State League, 2011, with a Cubs affiliate) and likes what he sees in Portland.

“The only team I can kind of compare to is the team I was on in the Florida State League, when we won,” he said. “But even then, we didn’t have the chemistry we have here.”

That chemistry looked in doubt when the Sea Dogs kept losing prospects – good players, yes, but also clubhouse leaders.

“It’s hard to replace the productivity from players like (Blake) Swihart, (Henry) Owens, Mookie (Betts), (Matt) Spring and those type of guys. They were also (key) guys in the clubhouse and on bus trips.

“I think that’s what some of the guys were worried about was being able to repeat that upbeat tempo every day. But we’ve had guys come up and we haven’t missed a beat.”

Portland has kept cruising along, especially with pitching.

Owens is in Pawtucket, but Wednesday’s starter for Portland, Brian Johnson (10-2, 1.75 ERA), has put up numbers equally as impressive. His ERA is the lowest in the Eastern League since 1985 (Brad Arnsberg, Albany, 1.59).

And tentatively following Johnson are Justin Haley (3-2, 1.19) and Eduardo Rodriguez (3-1, 0.96).

Binghamton has also lost some prospects, including three recently called up to the majors – second baseman Dilson Herrera, catcher Juan Centeno and pitcher Dario Alvarez.

But there is still plenty of talent on a team that went 83-59, one of the best records in the minor leagues, but overshadowed by Portland’s stellar mark.

Plus the Mets have promoted some prospects, including one with a familiar name. Infielder Gavin Cecchini, a first-round draft pick and younger brother of Red Sox prospect Garin Cecchini, is with Binghamton.

Sea Dogs fans might be interested to see Cecchini. But it is another new player that will draw the spotlight this week.

The Red Sox have invested millions for Castillo to help them win championships. The Sea Dogs would like that process to begin immediately.