SAN FRANCISCO — Longtime San Francisco 49ers center Eric Heitmann has been placed on season-ending injured reserve, clearing roster room for the addition of new linebacker Thaddeus Gibson.

The Niners (2-6), in their bye week after beating the Denver Broncos 24-16 in London on Sunday, claimed Gibson off waivers from the Pittsburgh Steelers.

The 30-year-old Heitmann was listed out with a neck injury, though he hadn't played all season after breaking the fibula in his left leg early in training camp Aug. 9. He was expected to miss up to two months and returned to practice Sept. 29. David Baas took his place on the starting offensive line.

Heitmann, a ninth-year pro out of Stanford, was going to miss at least another four weeks with a neck injury that also happened in training camp.