Thorpe is an undrafted free agent who joined the Chiefs over the summer. He comes from Auburn where he played in 51 games. He was signed to the Chiefs practice squad on Sept. 1.
Mattison was signed to the Chiefs on Sept. 26, after Rodney Hudson went down for the year. He was signed, along with Russ Hochstein, as a reserve lineman as the Chiefs transition Ryan Lilja to center and rookie Jeff Allen to guard.
Back in the Chiefs initial depth chart, Thorpe was listed as a right cornerback.
Here's a picture of the new Chief in action: