The whole point of the fourth preseason week is to avoid serious injuries. It's an almost impossible task.
Dan Hanzus did a great job recapping all the action Thursday night in our last "what we learned" of the preseason, but we wanted to point out the biggest injuries here.
1. Baltimore Ravens outside linebacker Courtney Upshaw re-injured his shoulder during the game against the St. Louis Rams. He'll undergo an MRI on Friday, and coach John Harbaugh admitted he was concerned. This could clinch Sergio Kindle's spot on the team.
3. Cleveland Browns rookie linebacker James-Michael Johnson hurt his left oblique against the Chicago Bears. The fourth-round draft pick was expected to start in place of Scott Fujita early in the season. Cleveland is very thin at linebacker.
5. Kansas City Chiefs quarterback Brady Quinn won the backup job, but he hurt his neck during his final preseason performance. Ricky Stanzi would have to back up Matt Cassell if Quinn's injury is serious.
6. Pittsburgh Steelers rookie inside linebacker Sean Spence suffered what appeared to be a serious knee injury Thursday night. The Steelers already were without three of their top six linebackers, although they are hopeful James Harrison can be ready for the opener.Follow Gregg Rosenthal on Twitter @greggrosenthal.