The news was a shock to Seattle's players, who didn't find out until a few hours before their game against the Twins on Wednesday, but they had no trouble gushing over the man who served as a boyhood idol to many of them.
"I grew up with Ken Griffey Jr. being the best player in baseball, and to get to know him on a personal level is something that, obviously, a lot of kids wished they could have done. I was fortunate enough to be one of those kids," shortstop Josh Wilson said. "I'm going to miss just being able to talk to the guy. ... Seeing him smiling and joking around, coming up and trying to squeeze the [air] out of my rib cage every day -- I'm going to miss that, too."
Perhaps no player could claim a stronger connection to Griffey as a youngster than Matt Tuiasosopo. The infielder grew up in the Seattle area making trips to the Kingdome to watch Junior play, and meeting Griffey in the dugout along with the rest of his 12-year-old All Star team stands out as a special memory.
"I wasn't even a lefty, but I would act like him from the right side," Tuiasosopo said. "He put Seattle on the map for baseball back in the day. ... It's been really special being able to be a part of this team and play with him and learn from him every day. That's something I'll always remember and tell my kids about. He's been a great teammate, and one of the best guys I've ever played with."
While Griffey helped inspire Tuiasosopo, he unintentionally gave reliever Ryan Rowland-Smith's career a kick start. In his Major League debut with the Mariners in 2007, Rowland-Smith notched his first strikeout against Griffey, who was then playing for the Reds.
That served as the Australian's "Welcome to the Big Leagues" moment, and he said he laughed about it with Griffey when he returned to Seattle.
"He had a huge impact on the game here, but also in Australia," Rowland-Smith said. "He was one of the handful of guys you could relate to as a young kid. To come in and get to face him, then talk to him about it a few years later, was a pretty cool experience."
Griffey's contribution to baseball in Seattle isn't lost on his teammates, as several pointed to his career as the main reason why their club is where it is today. Mike Sweeney, who will likely serve as the team's main designated hitter upon Griffey's retirement, was quick to sum it up.
"Without Ken Griffey Jr., we wouldn't have the year we had last year, we wouldn't be building toward something this year, and quite frankly, we wouldn't even have Safeco Field," Sweeney said. "They wouldn't have built this stadium and kept the Mariners here in town had it not been for him."
"I think Milton Bradley said it best," Sweeney added. "He said, 'On a day like this, it should rain in Seattle.'"
Cubs manager Lou Piniella coached Griffey in Seattle from 1993-99, and had a front-seat view during the prime of his career. In 1993, Griffey put together an eight-game home-run streak, and he won Gold Gloves from 1990-99.
"Junior was one of the finest young men I've ever had the opportunity to manage," Piniella said. "When we were in Seattle together, I believe he was the best player in baseball, and it was truly an honor to be his manager. As great a player he was, he is an even better person. I salute his Hall of Fame career."
Griffey struggled at the plate this season with a .184 average and no home runs, but he still impacted the team with his presence in the clubhouse. His arrival last year is credited with lightening the mood, a change of mindset that helped result in a 24-game turnaround from the dismal 2008 season. That's the side of Griffey that will be toughest to replace right now.
"There's going to be a big void that will never be filled," Sweeney said. "You can't match a Ken Griffey Jr. His charisma, what he's accomplished on the field, his heart. You can't replace Ken Griffey Jr., on or off the field."
But the Mariners will have to, and there was a clear sign Wednesday that the lighthearted, fun atmosphere Griffey brought to town isn't going anywhere.
As a throng of reporters and TV cameras interviewed players on the field during batting practice, reliever Shawn Kelley and bullpen coach John Wetteland took turns tripping and making dramatic falls behind their teammates in hopes of getting some camera time.
"I don't know if [Griffey] would do that, but me and Wetteland have always wanted to trip and fall behind someone getting interviewed and make it on ESPN or something," Kelley said. "That'll still be here with him gone.
"We'll still have a lot of fun and do what we did because of how he showed us to play the game, and have fun winning or losing. He's touched a lot of people, and there are a lot of guys in this clubhouse who have learned a lot from him. We'll continue to be the same group, but we'll miss him."
Mike McCall is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.