"The team turned over its personnel through the years, but Harry Kalas was always there calling the game," Costas said. "He was a great announcer. You couldn't convince someone in Philadelphia that there was anyone better to call a game than Harry Kalas.
"He was what baseball sounded like to you in Philadelphia."
Kalas had been the Phillies' voice since 1971, and for six seasons prior to that had broadcast Astros games. In addition, he was a respected broadcaster for the NFL, and the recent voice of NFL Films.
"He died with his boots on, so to speak," said Hall of Fame broadcaster Ernie Harwell. "I think if you had a choice and God gave you the option, you would take that option.
"He was certainly one of the game's great broadcasters," Harwell added. "I know he was a very popular figure in Philadelphia. He's going to be missed."
Harwell wasn't the only Hall of Fame announcer mourning the passing of Kalas on Monday.
Dodgers legend Vin Scully, for example, knew Kalas for almost 40 years and said he would always go chat with Kalas when the Dodgers played the Phillies.
"He was a remarkably talented broadcaster and a Hall of Fame broadcaster, but more than that, he was a great human being. He was a great pal," Scully said.
"He was a marvelous broadcaster and a wonderful human being. And I know the city of Philadelphia will be in mourning, because they love him back, and they should. He was that kind of a guy."
Another Hall of Famer who admired Kalas was Milwaukee Brewers voice Bob Uecker, who went into the broadcast wing of the Hall in 2003 as a Frick Award winner, one year after Kalas.
"I'm sad today," Uecker said. "He's one of my all-time favorite people. An easy-going guy, and a great broadcaster for the Phillies and NFL. What a versatile, talented guy, and he never let you know. He was just Harry.
"He always reminded me of a character from [the 1942 film] 'Casablanca.' Baggy pants, the white shoes. He'd have a hot toddy every once in a while. He was just an easy-going guy, and he was the same guy in the booth. If you didn't like Harry Kalas, you didn't like anybody."
One of the people who liked Harry Kalas a lot is Cincinnati Reds Hall of Fame broadcaster Marty Brennaman.
"When a person passes away who has any degree of celebrity, they'll say he was a great ballplayer or a great actor or a great announcer," Brennaman said. "Harry Kalas was just a great person. Often times, that part of it is overlooked.
"He and I had a great relationship. ... He was just a decent, decent person. I guarantee you he will be loved and remembered in Philadelphia as much for being the kind of person he was as he was in his chosen profession, because he was a hell of a guy."
Another Hall of Famer who remembered Kalas on Monday was Kansas City Royals broadcaster Denny Matthews.
"I think just the unique voice and the unique style made him very much an individual, which is pretty cool," Matthews said. "Very deliberate, very slow, interesting style."
Longtime Atlanta Braves broadcaster Pete van Wieren said he and Kalas were "dear friends."
"We had the opportunity to spend many years broadcasting together and enjoying other activities away from the broadcast booth," van Wieren said. "There are certain broadcasters that are much more than just voices for their team. Some of them are iconic figures for the game, and Harry was one of those broadcasters. I don't know anybody who didn't like him."
Orioles play-by-play man Gary Thorne certainly did.
"It is the end of an era," Thorne said. "He's of a time when there were singular names on the air connected to ballclubs and part of the fabric of the city."
One man from Kalas' city, WPVI-TV news anchor Jim Gardner, agreed.
"For me, he was the voice that meant the Phillies," Gardner said. "For me, baseball always brought you back to your youth. He spoke the language of your youth."
The loss was a very personal one for Pat Hughes, the Cubs announcer who has produced a CD series with noted baseball broadcasters, including "Harry Kalas: Voice of the Phillies."
"I just loved the guy," Hughes said Monday. "He was somebody I admired as a young man growing up trying to get into the business. I was struck by his voice and how clear and strong it was. Then I realized beyond that, he was really a great announcer. He knew what he was talking about. He could build the drama in a game.
"I loved hearing him do the voiceovers on NFL Films," added Hughes, alluding to Kalas taking over for the also legendary John Facenda. "It was a voice I never got tired of hearing. Every time I heard it, it sounded fresh and vibrant and good."
Eric Nadel, whose 31-year run in the Rangers' booth is one of the longest in history, said, "Harry was definitely one of the all-time greats in our business and arguably had the very best voice. But he was far more than just a voice. He used a combination of personality, humor and tremendous warmth to entertain the audience and endear himself to them. You can't do that with just a big voice."
"For people in broadcasting, he was one of those guys with unmistakable pipes. Unfortunately, he went before his time," said Rockies television play-by-play man Drew Goodman.
"The thing that makes broadcasters unique is the richness of their voice and their passion for the game. Harry had both of those," said Atlanta's Chip Caray, whose late grandfather Harry was inducted into the Ford Frick wing of the Hall of Fame in 1989 -- 13 years before Kalas received the same honor.
"When you think of the greatest ambassadors of the game, Harry was certainly one of those guys," Caray added. "The passion he had while calling games ... was a real inspiration for young broadcasters, like myself.
"He was truly a treasure. He was a mentor and a friend. People will say that the game won't be the same without him, and it won't."
"The Phillies have lost one of their icons," said Seattle's Dave Niehaus, another Frick Award winner (2008). "I've always been a huge fan of his. It's a great shock. A great loss."
Hughes and Caray were just two younger voices who followed Kalas into the booth and received his help and guidance.
"He was so nice," Hughes said. "He didn't have a mean bone in his body. He was friendly, sincere, still humble, never would brag. He's a Hall of Fame announcer, one of the best ever, and he just acted like a regular guy. He taught me a lot about how to act and treat other people."
Another of those youngsters was the Angels' Terry Smith, who grew up in Philadelphia idolizing his future mentor.
"My uncle was a friend of Harry's, and he told Harry of my interest in sportscasting, specifically in baseball," Smith recalled. "I sent him an audition tape. To this day, I still have the letter he sent me ... a very nice letter critiquing my tape.
"One of the things he had in that letter, and it kept me going in my profession, was that there was no doubt in his mind that I would be a Major League announcer if that's what I wanted to do. I've had that letter for over 25 years.
"His influence obviously has rubbed off on me. What I always knew about Harry was how well-prepared and descriptive he was. I'm very sorry he's gone, but he had a great life and influenced a lot of people."
Houston veteran Milo Hamilton, a fellow University of Iowa grad, called Kalas "his best pal." Hamilton would always greet him with "Hawkeye, how you doing?"
"[Jack] Buck and I were very close, and the same thing with Harry. And now my two best pals in the business are gone," Hamilton said.
"He had a distinctive voice and style. He had great ethics, he was a terrific guy. He was very close to the ballclub. He had a lot of friends. What really broke him up was when Richie Ashburn passed away. That was a big loss for him, when Whitey died. And this is a big loss for all of us. He was very popular with the city of Philadelphia."
Dewayne Staats, who broadcasts for Tampa Bay alongside Kalas' son, Todd, said Harry Kalas was born to be a baseball play-by-play man.
"Harry was the personification of taking his gift and doing what you're supposed to do with it," Staats said.
"He enjoyed it. It's a great gift. And he made sure that he took full advantage of that. And as he transitions from this life into the next one, what better place to do it than at the ballpark, in the booth? And if Harry could have written it his way, that's exactly the way he would have written it."
Dave Van Horne of the Marlins, into his 40th season of broadcasting baseball, called the news of Kalas' death "Tragic, shocking."
"Very sad day," Van Horne said. "I lost a friend, and baseball lost a legendary voice, and the Phillies family, and the Phillies fans, are going to miss him terribly."
Colorado radio voice Jack Kingery saw and exchanged pleasantries with Kalas on Sunday, after the Phillies wrapped up a series in Denver.
"We said we were looking forward to seeing each other again in August when the Rockies got to Philadelphia," Kingery recalled. "You mean all that, but certainly when something happens like this, it brings it home."
Arizona D-backs radio play-by-play man Greg Schulte remembered Kalas as a man happy to be involved with baseball.
"He always had a smile on his face and had something nice to say," Schulte said. "He was just a pleasant man to listen to. ... The bottom line is that Harry went out doing what he wanted to do in the broadcast booth. He will be dearly missed."
Jon Miller of ESPN and the Giants deviated slightly from others' somber reminisces.
"I'm happy for Harry, because he got to broadcast the Phillies winning the World Series and Opening Night when they had all the ceremonies and raising the World Series flag," said Miller, who covered that April 5 Citizens Bank Park opener and spent quality time with Kalas.
Added Miller, "It's a loss for the game, because Harry was synonymous with the game. His legacy will be felt for a long time to come in Philly. Two or three generations of fans were taught the game by Harry, taught to love the game and taught to love the Phillies."
The rich-baritone Facenda, the man whom Kalas replaced with NFL films, was often referred to as "the voice of God."
Harry can now hear the real thing up close, and share his baseball stories with the highest authority.