Emerging Melbourne youngsters Jack Grimes and Stefan Martin have both signed with the AFL club for another two seasons.

Grimes, 20, has shown promise in 11 games as a running half-back this season after making his AFL debut in the final round of 2008.

Former basketballer Martin, a 22-year-old 198cm key position prospect, has played all but two games this year, having notched his first eight games in the latter stages of last season.

Demons list manager Tim Harrington said both were showing exciting signs.

"Jack has shown maturity beyond his years with the football and leadership he has displayed since arriving at the club," he said.

"He is only a 12-game player, but he plays the game like a 50-game player and we think he can go on to play a major role for the Melbourne Football Club in the future.

"Stef is still developing as a player, but his potential for improvement is high."

Brought to you by AAP © 2024 AAP