SARASOTA, Fla. -- Ken Griffey Sr. abruptly resigned Friday from the Cincinnati Reds coaching staff but will remain with the team as a consultant.

Manager Bob Boone said he didn't see the resignation coming.

"It caught me completely by surprise," Boone said. "I wasn't aware of anything."

The Reds gave no reason for Griffey's decision. He will become a special consultant to Reds general manager Jim Bowden, switching jobs with Jose Cardenal, who replaces Griffey as first-base coach.

Griffey, 51, was not immediately available for comment. Outfielder Ken Griffey Jr. was surprised to learn that his father had quit.

"I only talked to him for a minute and said that I'd call him back," Junior said.

Griffey Sr. played for 19 seasons and was the right fielder on Cincinnati's "Big Red Machine" championship teams in 1975 and 1976. He was entering his sixth season as a Reds coach.

Griffey Jr. returned to his hometown in February 2000, in part because his father was a Reds coach and he wanted to be closer to his family. Griffey Sr. was briefly hospitalized for chest pains that season.

Junior said it will be different not having his father around.

At least "last year when he missed some time when he was under the weather, I knew he'd be back," he said.