Denver Broncos starting defensive end Jason Hunter underwent triceps surgery Wednesday and will miss four months.

Hunter became the second starter to suffer a serious injury during Tuesday's practice after right guard Chris Kuper fractured his left forearm. Kuper will miss 4-to-6 weeks.

"Jason Hunter did not participate today. He had triceps surgery he'll be out 4 months," head coach John Fox said.

The 28-year-old Hunter suffered his injury while slamming into a blocking sled during drills.

Hunter had moved ahead of Robert Ayers in the lineup just two weeks ago.