Washington Nationals’ lineup for 2nd of 3 with the Philadelphia Phillies in CBP...

Dusty Baker told reporters before last night’s series opener in Citizens Bank Park that he had already decided to keep Bryce Harper out of the lineup for the first game of three with the Philadelphia Phillies before the team’s trainers told him Harper’s groin was still a little sore.

Harper tweaked his groin on a diving catch in right field during the series finale with the Arizona Diamondbacks in Washington on Thursday afternoon, but the Nationals’ slugger said he hoped he’d be able to play in Citizens Bank, where he’s enjoyed some success early in his career.

Baker said after Thursday’s win that Harper was day-to-day for now.

In 38 games and 158 career plate appearances in CBP, Harper’s put up a .296/.361/.627 line with five doubles, three triples and 12 home runs.

The fact that it was raining all day in Philadelphia on Friday didn’t help, but Baker said he had made up his mind beforehand.

“I had already given him [the game] off prior to waking up this morning,” Baker said, as quoted by MASN’s Mark Zuckerman, “but the wet field certainly didn’t help at all.”

“He’s a little sore. Like I said yesterday, he’s day-to-day. I said I’ll check with him daily. I didn’t check with him today, but I checked with the trainers. Hopefully he’ll come back sometime this weekend.”

The Nationals took the series opener with the Phillies without Harper in the lineup.

Stephen Strasburg, Ryan Zimmerman and Anthony Rendon all homered in the 4-2 win, with Rendon driving in the fourth run on a bases-loaded single.

Tonight, in the second game of three, Harper is out of the lineup again, with Rafael Bautista getting the start in right field.

A.J. Cole is on the mound for the Nationals tonight, after serving the final three games of the five-game suspension handed down by Major League Baseball after he threw behind Pittsburgh Pirates’ third baseman Jung-ho Kang late last season.

In four starts at Triple-A Syracuse before he was called up this week, the 25-year-old right-hander was (1-1) with a 6.63 ERA, 4.73 FIP, 10 walks (4.74 BB/9) and 14 Ks (6.63 K/9) in 19 IP.

Here’s the lineup that will back Cole up tonight in Citizens Bank Park: