He never got to call the game.
Kalas, in his 39th season as narrator of all things Phillies, collapsed in the broadcast booth around 12:20 p.m. and died after being rushed to a nearby hospital. He was 73.
Phillies players and personnel were informed of the news by club president David Montgomery in a somber pre-game meeting.
"Sadly, I must confirm that we lost Harry," Montgomery, fighting back tears in a hallway outside the visiting clubhouse, told a large group of reporters who had assembled after hearing that Kalas had been sticken.
"We lost our voice today," Montgomery added. "Harry loved our game and made a tremendous contribution to our sport, and certainly to our organization."
The Phillies had been scheduled to visit the White House tomorrow, but Montgomery said the visit had been postponed indefinitely.
Players were not available for comment before the game.
"They're stunned," Montgomery said. "When you have a presence like Harry Kalas, anybody that played for us, it's an immediate point of connection with our club because Harry is the Phillies."
The Nationals organization, hosting its home opener, honored Kalas' memory with a moment of silence before the first pitch.
"He was the heart and soul of the Phillies organization," the stadium public address announcer told the crowd.
As Kalas' picture flashed on the video board above rightfield in the hushed stadium, a fan shouted: "We love you, Harry."
Chris Wheeler, a longtime broadcaster partner of Kalas, wondered if the Phillies could have played if the game weren't on the road.
"It would have been hard to play if this had been a home game," Wheeler said.
The team did not say how the broadcast team will be affected by Kalas' absence.
Wheeler recalled that he joined the Phillies in 1971, the same year as Kalas.
"He helped me when I went into the broadcast booth," Wheeler said. "He taught me a lot about how to be a professional and do the job. We spent a lot of time together."