That's why the news was so difficult for those close to Killebrew, who spent nearly his entire career with the Twins organization, including parts of seven seasons with the Washington Senators before the franchise moved to Minnesota in 1961.
"You know him from being a great ballplayer, a great home run hitter, but you don't know how great a person he was if you didn't meet him," said Twins great Tony Oliva at a press conference at Target Field on Tuesday. "When I first came here to Minnesota, I didn't speak one word of English. And he called me 'rookie', and still 50 years later he called me 'rookie.'
"He was a superstar and he treated me [the] same way as [if] I was one of the big guys on the ballclub," Oliva continued. "I never saw Killebrew put anybody down. I keep saying to everybody that he was too nice to be a baseball player. Because I never saw him get mad, I never saw him throw a helmet, I never saw him throw a bat and I never saw him do nothing but only help people. And as a teammate, I don't think I could have a better teammate or better friend than Harmon Killebrew."
Killebrew and Oliva, who played together for 14 seasons, were especially close. They served as ambassadors for the Twins and were members of the team's Hall of Fame. Oliva flew to see Killebrew on Saturday, and was happy to see his old friend after spending time with him during Spring Training this year in Fort Myers, Fla.
"He said, 'You know I love you. You know I love you guys,'" Oliva recalled of their meeting before he left Sunday.
Oliva traveled to Arizona with former Senators and Twins first baseman Julio Becquer, who said Killebrew "was like family" after spending so much time together over the years.
"He was more than a friend, after 50 or some years together," Becquer said. "And he was a great human being. He was a great guy, a great fan, one of those guys that have that aura that's approachable, not only liked but loved by many, many people."
Hall of Famer Rod Carew, who wasn't able to attend the press conference, also had nothing but positive things to say about Killebrew after playing the first eight years of his career with the noted slugger.
"This is a sad day for all of baseball and even harder for those of us who are fortunate enough to be a friend of Harmon's," he said in a statement. "I can never thank him enough for all I learned from him. He is a consummate professional who treats everyone from the brashest of rookies to the groundskeepers to the ushers in the stadium with the utmost of respect. I would not be the person I am today if it weren't for Harmon Killebrew. He is a Hall of Famer in every sense of the word."
Bert Blyleven, who will join Killebrew and Carew in the Hall of Fame this summer, fondly remembered meeting Killebrew for the first time in 1970, when Blyleven was just a rookie in Twins camp and Killebrew was coming off his MVP season from the year before.
"Being a rookie pitcher, Harmon treated me like one of the guys," Blyleven said. "It was really neat. More like a son than a teammate because I was so young. But when I think of Harmon Killebrew, I think of class. Not just a Hall of Fame player but a guy who just loved life and gave so much back."
Blyleven, who also serves as a Twins television broadcaster, added that Killebrew was as big of a star in the Midwest as any player in franchise history, calling him the face of the Twins.
"I think he probably left an impression in this five-state area bigger than any politician or whoever," Blyleven said. "Harmon Killebrew is Harmon Killebrew. How do you put one word on Harmon Killebrew? You can't."
Former Twins infielder Frank Quilci, who also served as Killebrew's manager from 1972-74, concurred with Blyleven, as he felt Killebrew represented the Twins organization more than any other player.
"He was really the face of the organization, because of his strength and because of the way he played the game and the way he carried himself," Quilici said. "But there was an Apache in him, believe me. If he got angry, he got angry inside himself."
Even those who didn't get a chance to play with Killebrew were in awe of his career and his grace, including Jack Morris, who grew up St. Paul and helped lead the franchise to a World Series title in 1991. Morris now serves as a radio broadcaster for the Twins and remembered watching Killebrew while growing up.
"Harmon is so many things to so many people here in Minnesota, but to me he was my boyhood idol," Morris said. "Everybody wanted to be Harmon Killebrew when they were a little kid. But he was an even a better person once I got to know him."
Morris choked up at the press conference, recalling how much Killebrew meant to him, as his childhood hero was so much more than just a famed home run hitter.
"I think the one thing that hits home the most with Harmon is his strength, not as a player, but as a person," Morris said. "And his kindness and the strength in his kindness, to me he was a real man. He was all man, because he loved so much. He is this family that we call the Minnesota Twins.
"I think at this point, I think it's more of a celebration of his life than it is a mourning of his death for me. I'm going to always remember the good in Harmon, to remember the innocence of being a young kid who just looked up to a guy you didn't know because of what he did as baseball player, something that you hoped maybe someday you could be like."
Former Twins first baseman Kent Hrbek, who also grew up in the Twin Cities area, had a similar experience with Killebrew, as he looked up to Killebrew before finally getting a chance to know him while playing with the Twins.
"Being a kid growing up in the area, you had idols when you were playing the game of baseball, not only this guy sitting next to me in Tony Oliva, but Harmon Killebrew," Hrbek said. "I think Harmon has become something of a Paul Bunyan in the state of Minnesota."
Hall of Famer Paul Molitor also praised Killebrew, especially for his work off the field as he was very active in the community. Killebrew returned to an official capacity within the Twins organization in 1997 as a special assistant. In that role he became a regular participant at TwinsFest, the Twins Winter Caravan and other major community-oriented events. And he also founded the Killebrew Foundation which helped raise hundreds of thousands of dollars for many charitable organizations across the country.
"Harmon only spent, what, a quarter of his life as a major league player and the other three quarters were as a tremendous human being included with his time as a player," Molitor said. "I was so impressed with his servanthood, his foundation, the people he touched. The way he gave back, it was a tremendous example for someone like myself."
Many former teammates also shared their reactions on Friday, when Killebrew announced he was entering hospice care, as his battle with esophageal cancer was nearing its end.
Phillies manager Charlie Manuel used class as an adjective when asked about Killebrew, as he played the first four years of his career with him and compared him to current Twins designated hitter Jim Thome.
I used to call him 'Fat Man,' Manuel told reporters on Friday. "He was big and strong. Back then he weighed 230. He was hard. He was really built like a fireplug. He was about 5-11. Big and strong. Real strong legs. He could hit, man. He had a good swing."
Former Twins pitcher Jim Perry recalled his relationship with Killebrew. Perry lived next door to Killebrew and played with him for 10 years, including three trips to the postseason in 1965, '69 and '70.
"I knew Harmon really well and he was a good friend," Perry said by telephone on Friday. "He was a really good guy to have on the team because the guys really looked up to him. He handled himself well with the writers and everyone around the league. So it was a big thing. It's nice to be in the Hall of Fame, but it's about the off-the-field stuff, too."
Perry added that Killebrew's impact stretched further than the playing field, as Killebrew had an equally amazing presence in the clubhouse -- not just because of his talent, but because of his personality.
"He wasn't just a great player, he was a great leader," Perry said. "You could depend on him to get a big hit in the game. It was always nice to see him come up to the plate. But he was also a great guy in the dugout and the clubhouse."
Fellow former Twins pitcher Jim Kaat played 15 years with Killebrew, including two seasons in Washington before the move to Minnesota, and talked with Killebrew on Monday. He said Killebrew was the consummate Twins player and one that many have emulated over the years.
"He really is the face of the Twins franchise," Kaat told reporters in New York on Friday. "I think he's the main reason the Twins have a reputation for being a gentlemanly organization. I think it all started with him."
Kaat recalled Killebrew's raw power -- he hit more than 40 home runs eight times and led the American League in homers six times.
"There are two guys that could make you stop when they hit these towering home runs," Kaat said. "That was Mickey [Mantle] and Harmon. In the pre-cable TV days, he didn't get that much exposure. He hit them at key times, good pitchers in key moments."
It was a statement echoed by Oliva, who said Killebrew was the premier slugger of his era back when home runs were still relatively rare.
"I've never seen a home run hitter like Killebrew," Oliva said. "When I played, there was no better home run hitter than him. And in those days, a lot of those ballparks were big and the ball was more of a dead ball."