The Ravens have placed a couple of defensive backs on IR, as both Chris McAlister and Dawan Landry are out for the remainder of the 2008 season.A McAlister as knee surgery in Coral Gables, Flordia on Monday according to sources.A He also had fallen out of favor with new head coach John Harbaugh, and he saw little to no playing time during large parts of the 08 season. The team did make moves to fill their spots, as they signed LB Robert McCune and WR Marcus Maxell.