Bradley left the team before Tuesday night's game against the Baltimore Orioles to be with his wife, Erin, who is expecting the couple's first child. Players typically get at least three days of paternity leave, according to Red Sox manager John Farrell, who said Bradley isn't expected to rejoin the club until after it returns to Fenway Park on Friday.
Bradley is having a breakthrough season for the Red Sox, batting .331 with a .409 on-base percentage, nine homers and 37 RBIs in 50 games. He recently had a 29-game hitting streak, longest in the majors this season. After hitting a home run in Monday's 7-2 victory over the Orioles, he is one homer shy of matching his single-season career-high from last year.
Castillo, who signed a seven-year, $72.5 million contract in August 2014, has been a disappointment for the Red Sox. He lost the left-field job in spring training to utilityman Brock Holt and was sent to Triple-A in mid-April to get regular at-bats. He is batting .241 with a .302 on-base percentage, one homer and 13 RBIs in 37 games.
"There's been some inconsistencies on the offensive side of things," Farrell said. "I don't know that he's really gotten on track as we've seen in the past."
Young, meanwhile, was signed as a free agent last winter to play mostly against left-handed pitchers. After a slow start, he is batting .258 with a .785 OPS, one homer and six RBIs in 69 at-bats in 29 games.