Port Adelaide young gun Todd Marshall will be sidelined for six weeks after having surgery on a broken thumb.

Marshall suffered the injury to his right thumb while smothering the ball during their AFL loss to St Kilda on Saturday night and had surgery on Sunday.

Given the condensed nature of the fixture, Marshall is set to miss a large chunk of games in a significant blow to the ladder-leading Power.

Port Adelaide are about to play four games in less than three weeks, with upcoming clashes against Melbourne, the Western Bulldogs, Richmond and Geelong.

Marshall, 21, had played all eight games for Port Adelaide this season, booting nine goals and averaging four score involvements and 3.8 marks per game.