Vikings head coach Leslie Frazier says the knee injury to tight end John Carlson of Litchfield is not a serious one. Carlson did not practice yesterday and Frazier confirmed the pass catcher suffered a sprain of his MCL, which will leave him off the field for about two weeks. Carlson was signed as a free agent in the offseason. His teammates will have two more scheduled practices today in Mankato. The Vikes will workout tomorrow and Saturday and get Sunday off.