Carpenter, the Seahawks' top pick in the 2011 draft, suffered the injury during Wednesday's practice and underwent an MRI later that night.
After starring collegiately at Alabama for two seasons, Carpenter was selected with the 25th overall pick in April's draft. He started all nine games for Seattle this season.
In last Sunday's win over Baltimore, the Seahawks lost rookie right guard John Moffitt for the season with a right knee injury.
Paul McQuistan is expected to start for Moffitt when the Seahawks visit the Rams on Sunday, while Breno Giacomini will fill in for Carpenter.