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(SportsNetwork.com) - The Boston Red Sox won't get a chance to defend their World Series title this October, but that doesn't mean they can't use September to create a little excitement for next season.

The Red Sox are expected to debut outfielder Rusney Castillo on Wednesday night in the second contest of a three-game series with the Pittsburgh Pirates.

Projected as Boston's leadoff hitter of the future, the Cuban Castillo signed a seven-year, $72.5 million deal on Aug. 23 and has been playing with various minor league clubs for Boston since. That run of games ended on Tuesday night with Pawtucket's Triple-A championship game.

The Red Sox will get some looks at the speedy Castillo down the stretch as they prepare to use him in a bigger role going forward.

"Yeah, I don't expect him to be an everyday player here. He's gonna get games played, that's for sure," Boston manager John Farrell told his team's website. "But we've got other guys here as well. We'll strike a balance with that."

Castillo's first major league at-bat is likely to come against Pirates starter Francisco Liriano, who has been red-hot as of late as his club makes a run at a playoff spot.

The left-hander has posted a 0.67 earned run average over his last four starts and has hurled a total of 14 straight scoreless innings over back-to-back wins. He logged eight innings of four-hit ball on Thursday at Philadelphia, striking out 12 to improve to 5-10 on the year with a 3.53 ERA.

"He's been throwing the ball well," Pittsburgh catcher Russell Martin said about Liriano. "The wins and losses aren't indicative of how well he's pitched this year."

Liriano has allowed just two runs over his past 27 innings and is 1-3 lifetime versus Boston with a 7.01 ERA.

The Red Sox counter with their own streaking hurler in Clay Buchholz, who has given up just four earned runs over a three-start winning streak.

Buchholz is coming off a win at Kansas City on Thursday, charged with three runs -- two earned -- on six hits and three walks over 6 1/3 innings with seven strikeouts.

The righty has pitched to a 2.10 ERA over his last four outings, but is still only 8-8 on the year with a 5.19 ERA.

Buchholz has never faced the Pirates, who won last night's opener 4-0. That kept Pittsburgh 1 1/2 games up on Milwaukee for the National League's second wild card spot and pulled the club within 2 1/2 games of St. Louis for first place in the NL Central.

Russell Martin hit a two-run homer in the second inning, Starling Marte added a solo shot in the sixth and Charlie Morton hurled five innings of four-hit ball in his return from the 15-day disabled list.

"It was nice for us to get out in front and create some separation," Pirates manager Clint Hurdle said.

Morton had been out since Aug. 15 due to a sports hernia, but returned to help Pittsburgh win for the ninth time in 11 games.

Anthony Ranaudo allowed three runs on four hits with three walks over 5 2/3 innings for the Red Sox, who had taken three of four over another playoff- hopeful club, the Kansas City Royals, coming in.

Boston matched Pittsburgh's seven hits on Tuesday, but went 0-for-10 with runners in scoring position and stranded eight.

"We had a number of opportunities...and we couldn't cash in," Farrell said.

These two clubs have not met since the Pirates won two of three in Pittsburgh during the 2011 season.