"I'd like to thank the Mariners organization for inviting me back to play in 2010," Griffey said in a statement. "While 2009 was an awesome experience for me, my ultimate goal is for the Mariners to get to and win the World Series.
"To that end, I look forward to contributing in any role that [manager] Don [Wakamatsu] sees fit on the field, and any manner I possibly can off the field."
Griffey, who will turn 40 on Nov. 21, batted .214, hit 19 home runs, drove in 57 runs and led the team with 63 walks in 117 games, an indication that even with his lowest career single-season batting average, he commanded the utmost respect from opposing pitchers.
His final home run of the season, coming on the next-to-last day of the season at Safeco Field, was the 630th of his career. Only Barry Bonds (762), Hank Aaron (755), Babe Ruth (714) and Willie Mays (660) have hit more.
Mariners general manager Jack Zduriencik finalized the deal early Wednesday morning and spoke to the media via a conference call from Chicago.
"We all realize what he meant to the team on and off the field," he said. "His leadership was special. He's excited about coming back, and we're excited to have him back.
"He's a great guy, a fun guy, loves life, loves baseball and loves the community. It's a real bonus for us to have him back."
Griffey recently underwent arthroscopic surgery to remove a bone spur in his left knee, which limited him to 11 games in the field during his homecoming season with the Mariners.
The surgery, which he would have had even if he had decided to retire, is expected to give him more mobility. The Mariners are encouraged by the medical reports they have received from Dr. Tim Kremchek.
"We feel really good about everything," Zduriencik said. "It apparently wasn't major, and there is nothing to be overly concerned about. We believe he will be in good shape and be ready to roll when he reports to Spring Training."
Exactly how much playing time Griffey will get remains to be seen.
"We'll see how this thing unfolds," Zduriencik said. "The positive part is he wants to be part of this program, and we're happy to have him back."
Wakamatsu, who attended an Arizona Fall League game on Wednesday afternoon in Peoria, agreed that there are too many questions left to be answered regarding the makeup of the roster before making a prediction on how much or where Griffey would play.
"It's way too early to predict, but the way he ended up last season shows that he can still contribute," Wakamatsu said. "Junior understands that there are no promises, but he wouldn't have made the decision to come back if he didn't feel he could contribute.
"With the surgery, and coming to camp in shape, I look for him to be a contributor."
Griffey was open to whatever 2010 might bring.
"Junior has no preconceived notions," his agent, Brian Goldberg, said. "He will prepare himself to play a lot, but will embrace whatever role Don has for him. It's a long season, and a lot of things, both expected and unexpected can happen."
Four of Griffey's home runs came during the Mariners' final homestand of the season, and it would have been some kind of exit -- if had he decided that a 21-year MLB career was enough.
But he told Zduriencik during the final weekend of the season that if the organization wanted him back, then he wanted to come back. Junior's Orlando-based family gave its blessing for his return.
"There are many players on this club excited about being teammates with Ken Griffey for another year," Zduriencik said.
Reliever Mark Lowe is one of them.
"When I heard about it, I got chills right away," Lowe said. "Being my favorite player growing up, I wanted him to come back. It's exciting to know that I will get to spend another seven months with the guy and laugh every single day."
Griffey helped turn a divided clubhouse a year ago -- so much so that former GM Bill Bavasi called the team "dysfunctional" -- into a cohesive unit that played hard and had fun from the first day of Spring Training to the final game of the season.
"I don't know if I'll ever have the opportunity to have a player who enjoys playing the game as much as he does," Wakamatsu said. "He's fun. He's infectious to his teammates. He's such a breath of fresh air."
Mariners fans thoroughly enjoyed the reunion season, and let their feelings be known during the final game at Safeco Field.
They chanted "One more year!" numerous times during the season finale against the Rangers.
After the game, a red-eyed Griffey spent almost an hour with reporters, acknowledging that the day was unlike any other during his career.
He went 1-for-4 in the Mariners' 4-3 victory, and along with Ichiro Suzuki, was carried off the field by teammates.
Afterward, Griffey said, "um, yeah" when asked if he wanted to return in 2010. But he also hedged a bit, seemingly content with riding off into the sunset and becoming a full-time husband and father of three kids.
"You never know," he said then. "If this is going to be the last one, it's tough."
But that single into right field won't be his last hit, or his last game.
Among other things, Griffey has an opportunity to tie Sammy Sosa for hitting home runs in the most ballparks. Griffey is one behind Sosa with 44 -- and can move into a tie when the Mariners play a three-game series against the Twins on July 30-31 and Aug. 1 at Target Field, the only new ballpark in the Major Leagues next season.
Griffey also has a chance to add more pitchers to his home run victims list.
Of the 19 home runs he hit last season, 15 of them were first-time victims. Junior has hit home runs off 407 different pitchers, second only to Sosa's 449.
He won't catch Sosa in 2010, but Griffey undoubtedly will add a few more names to his list.