Rusney Castillo drilled a sharp grounder to second base and took off. Three seconds later the future of the Boston Red Sox was standing on first base.

If the Cuban-born prospect was overwhelmed by the stage, he hardly looked it.

Nine months after defecting and barely three weeks removed from signing with the Red Sox, the rookie centerfielder went 1 for 4 in his major league debut as Boston fell to the Pittsburgh Pirates 9-1 on Wednesday night.

"I'm pretty satisfied with that being my first game," Castillo said. "Obviously I'd like a better outcome in terms of winning the game. But I was pretty satisfied with my overall approach and the way I stepped in today."

Castillo arrived in the Boston clubhouse early Wednesday afternoon following a 10-game dash through the team's minor league system. Following a short meeting with manager John Farrell, the 27-year-old who signed a seven-year, $72.5 million contract to spend the rest of the decade in the outfield at Fenway Park pulled on a No. 38 jersey and began what he hopes will be a lengthy and productive stay in Boston.

Though Farrell stressed the final two weeks of an otherwise lost year are simply a chance for Castillo to get comfortable as a big leaguer and that drawing any concrete conclusions is unwise, the early returns were promising. He beat out his first hit in the fourth and made a fine running catch in the cavernous left-center field gap at PNC Park an inning later.

"For his debut, first action, he didn't look overmatched," Farrell said.

The same couldn't be said for starter Clay Buchholz.

The lone holdover from the starting rotation that helped the Red Sox win a World Series last year surrendered six runs, five earned, in four rocky innings. Buchholz (8-9) gave up solo shots to Gregory Polanco and Neil Walker, ending a streak of 36 innings without allowing a homer.

"The last four or five games, I've made mistakes during the game but didn't seem to get hurt on them," Buchholz said. "I just ran into a club that's swinging the bats really well right now."

The Pirates have won 10 of 12 and improved to a season-high 11 games over .500 (81-70) in their pursuit for a second straight playoff berth. Pittsburgh moved 2.5 games in front of Milwaukee for the second wild card spot in the National League after the Brewers lost in St. Louis.

Francisco Liriano (6-10) won his third straight start, allowing one run in six innings. The left-hander has given up two runs or less in 11 of his 12 starts since the All-Star break.

Polanco wasted little time drumming Buchholz, who came in riding a three-game winning streak. The rookie drilled a Buchholz fastball into the seats in right for his seventh homer of the season and first since Aug. 10.

The lead ballooned to 4-0 in the second behind a two-run double by Clint Barmes. Walker golfed a Buchholz pitch into the first row of seats in right for his 21st homer of the season in the fourth, extending his record for most home runs in a season by a Pittsburgh second baseman.

Davis ended any drama in the fifth with a three-run homer to center, his 11th of the season and 10th with Pittsburgh. The Pirates have nine players with at least 10 home runs, a club record for a single season.

TRAINER'S ROOM

Red Sox: 2B Brock Holt continues to work his way back from a concussion sustained in a collision with Dustin Pedroia on Aug. 25. Holt is scheduled to meet with concussion specialist Micky Collins on Thursday. Farrell said Holt is doing daily vision exercises and running on a treadmill but has not started baseball related activities.

Pirates: RHP Charlie Morton reported no issues a day after pitching five shutout innings in his first start in a month due to a hernia issue. Manager Clint Hurdle said he's still hasn't made a decision on who will start when Morton's turn in the rotation comes up again on Sunday against Milwaukee.

UP NEXT

Red Sox: Brandon Workman (1-9) will try to end a nine-game losing streak when he makes his 15th start of the season. Workman's only victory of the season came on June 10 against Baltimore. His ERA is a season-high 5.27 after giving up five earned runs in three innings of a 10-6 loss to Baltimore last week.

Pirates: Gerrit Cole (9-5) goes for his third straight victory. The 24-year-old struck out six and walked one while working six innings in a 7-3 victory over Chicago in his previous start.