The Harpers announced the pregnancy Monday on social media. They welcomed son Krew Aron Harper on Aug. 22. Bryce, 28, and Kayla, 27, married in 2016.
"Girl dad!" Bryce wrote for the caption of a photo of the couple holding a sonogram of their daughter on social media.
"Evening things out this year with Baby Girl Harper," Kayla wrote for a post with the same photo.
Harper joined the Phillies in March 2019 with a blockbuster 13-year, $330 million contract in free agency. The six-time All-Star and 2015 National League MVP hit .260 with 35 home runs and 114 RBIs in 157 games last season.
Harper was one of the many MLB players who has voiced his desire to play a season in 2020 amid the coronavirus pandemic. He tweeted "tell us when and where" last week, in reference to players' union negotiations with MLB team owners about a resumed season.
MLB spring training games were canceled in mid-March and the season was scheduled to start March 26 before it was postponed due to the pandemic.
The Phillies closed their Clearwater, Fla., facility last week after five players and three staff members tested positive for the coronavirus.