PHILADELPHIA -- Spencer Howard's highly anticipated Phillies debut Sunday ended with Marcell Ozuna spiking his bat into the dirt and splintering the handle into shards. Ozuna was angry. It was the second time he struck out swinging on Howard's slider.

Howard can carry that moment into his next start.

"That was one of the high points of the day for me," Howard said, following an 8-0 loss to the Braves in Game 2 of a seven-inning doubleheader at Citizens Bank Park. "Take your victories where you can get them. To end on that, a good taste in my mouth, moving forward it'll be nice."

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The Phillies and Howard expect more reactions like that in the future. Howard is the No. 36 prospect in baseball, according to MLB Pipeline, because he has an electric fastball, three impressive offspeed pitches and a cool demeanor that makes him look and sound like a future ace. It was why Sunday was Philadelphia's most highly anticipated debut by a pitcher since Aaron Nola in 2015 and maybe even Cole Hamels in '06. Howard showed flashes of that potential, but he also showed room for improvement. He allowed four runs on seven hits (including two home runs) and one walk and struck out four in 4 2/3 innings.

"I was hoping for a complete-game shutout," Howard said. "That's what everybody would dream about. But just being able to compete at the highest level again, a dream come true. It's just exciting to be out there and face an All-Star lineup."

But what a week.

"It seemed like I was the last person to know in the United States that I was going to pitch today," Howard said.

Signs first pointed to Howard's arrival on Monday, when the Yankees and Phillies postponed Tuesday's game in New York because of the threat of rain. It created a twin bill Wednesday at Citizens Bank Park. Aaron Nola and Zack Wheeler pitched Wednesday, which meant the Phils needed a sixth starter Sunday.

It could have been nobody other than Howard.

But it wasn't easy. Howard last pitched in a game at the team's alternate training site in Allentown, Pa., on July 31. The Phillies scheduled him to pitch a five-inning game Thursday, but they instead turned it into a simulated game without the hitters taking swings.

The switch in the schedule was an obvious sign that the Phillies planned to promote him. Philadelphia's player development director Josh Bonifay finally made it official with a call on Friday.

"A bunch of my buddies texted me," Howard said. "Friends and family were really excited, so I kind of got that feeling. I just tried to stay as even-keeled as possible and not let the moment get too big."

Howard said he felt some nerves, even though there were no fans, family or friends in the stands because of the COVID-19 pandemic. (His family watched back home in Templeton, Calif.) But Howard pitched here during Summer Camp with no artificial crowd noise or cardboard cutouts of fans placed around the ballpark.

"The cardboard cutouts made a difference, surprisingly," Howard said.

Howard was not sharp, he acknowledged. The layoff probably affected him. The Braves took advantage on their way to a doubleheader sweep. They are an aggressive team and swung at the first pitch 13 out of 22 times. Atlanta first baseman Freddie Freeman took a first-pitch fastball on the outside corner in the third inning and hit an opposite-field two-run home run to hand the Braves a 2-0 lead. Ronald Acuña Jr. hit a first-pitch slider for an opposite-field solo home run in the fifth inning to make it 3-0.

"I liked his stuff," Freeman said. "I think he was a little bit excited. His offspeed pitches were up in the zone. You could tell he's got really good stuff. It's hard to judge anybody off their big league debut. He was so fired up."

Howard will have time to settle down, but where and when will he pitch next? He could start Friday, but Phillies manager Joe Girardi said Vince Velasquez is there for now, although no decision has been made. It is possible that Howard pitches out of the bullpen.

The bullpen certainly needs help. He could be a weapon there.

"I mean, whatever they need, I'm up for it," Howard said. "It would be a little adjustment, but I'm sure it's nothing too crazy."

But wherever Howard shows ups next, he expects to be better.

"A lot of work to do," Howard said. "I would say I would feel worse if I felt really sharp and pitched the same way I did. So I know what I need to work on. It's just time to get to work, I guess."