Serving as a guest analyst for MLB Network's draft coverage, Griffey -- who finished his career with 630 home runs -- said Bleday, 21, is "a whole lot stronger than I was at that age."
"I ain't have that," Griffey said of the No. 4 overall pick's power. "I'm a late developer. I didn't start having pop until I was 27."
Griffey had 294 home runs through his age-27 season in 1997. He had a career-high 56 home runs for the Mariners that year.
Bleday hit .353 with 26 home runs and 68 RBIs for Vanderbilt this season.
"He can swing it," Griffey said.
Miami can only hope Bleday follows in Griffey's footsteps. The Marlins haven't had a winning season since 2009 and haven't made the postseason since winning the World Series in 2003.
The MLB Draft continues Tuesday and completes Wednesday.