(Alex Brandon / AP) (Alex Brandon / AP)

Baseball Sunday mornings are generally lazy affairs. A handful of pitchers play toss in the outfield or the bullpen. They wheel the batting cage out, but only a few hitters bother to use it. Players and coaches attend chapel. The stadium stays quiet and fans file in after brunch or church.

Today was different. The Nationals handed out Bryce Harper bobbleheads to the first 15,000 fans. Lines formed outside the center field gate at 10:15 a.m. As chance would have it, Harper took full batting practice on the field for the first time since he went on the disabled list in early June, the latest test for his bursitis-addled knee. The session started at 11:30 a.m., right around the time gates open and fans clutching their new bobbleheads began filtering in.

The confluence of bobbleheads and batting practice created an impromptu amphitheater at Nationals Park. Harper cut loose with his swing, launching balls to left, into the opposing dugout bullpen and the red seats in early rounds of batting practice. Fans cheered when he blasted pitches into the upper deck to right field. Both Manager Davey Johnson and General Manager Mike Rizzo watched from behind the cage.

Between one round, as Kurt Suzuki and Chad Tracy took their turn, Harper chatted with hitting coach Rick Eckstein. He flexed both knees, nodded his head and stepped back in. He had the same ferocious swing, using his left leg to transfer weight from back to front. He wore baseball pants and a T-shirt that read, “Run Til They Tag You” with his image superimposed.

When Harper finished, he tossed his black bat on the grass toward the home dugout. As he walked to the mound to help pick up stray baseballs, the impromptu crowd of 10,000 or so roared.

“I had to give them what they came to see,” Suzuki said, deadpan, as he walked into the dugout.

Harper has not been able to condition much with his legs, but he has kept his upper body in shape with exercises that include a hand bike. As he walked off the field, he passed a pair of grounds groundskeepers. “He’s getting bigger and bigger,” one of them said. “He’s getting jacked, man,” the other replied.

Harper will likely begin his rehab assignment next week. Johnson said Harper will work out at Nationals Park on Monday and Tuesday, with an eye on possibly heading to Class A Potomac on Wednesday. For today, he put on an impressive, unique batting practice show. When Harper retreated to the clubhouse, he tweeted his appreciation for a cool, random moment. He wrote, “Well that felt unreal! #BP #Lovethefans”