Bryce Harper hits a grand slam against the Cubs

Philadelphia Phillies' Bryce Harper hits a grand slam during the ninth inning of the team's baseball game against the Chicago Cubs, Thursday, Aug. 15, 2019, in Philadelphia. Phillies won 7-5. (AP Photo/Chris Szagola)

The Phillies will be without their best offensive player as they begin a crucial three-game series against the Miami Marlins on Friday night.

Bryce Harper has been placed on paternity leave as he and his wife Kayla are expecting the birth of their first child imminently.

Baseball's collective bargaining agreement allows a player to spend up to three days on paternity leave. It was not immediately known whether Harper would miss the entire three-game series in Miami or join the team sometime over the weekend. After playing three games in Miami, the Phillies open a three-game series at home against Pittsburgh on Monday night.

Both Miami and Pittsburgh are last-place clubs and the Phillies need to take advantage of these matchups. There are 36 games remaining in the season and the Phils sit two games back in the NL wild-card chase.

Harper has been on a tear lately. He has nine homers, 20 RBIs and a 1.139 OPS in the last 17 games. He belted a go-ahead, two-run homer at Fenway Park on Wednesday night to help the Phillies pull off a two-game sweep of the Boston Red Sox.

The Phillies replaced Harper on the active roster with Maikel Franco.