New England Patriots star tight end Rob Gronkowski's right knee injury "isn't serious," according to a league source. Gronkowski got hurt during an overtime loss to the Denver Broncos. Gronkowski got it X-rayed and was able to walk under his own power with a limp. Gronkowski isn't expected to miss a significant amount of time. Follow me on Twitter: @AaronWilson_NFL Aaron Wilson covers the Texans for The Houston Chronicle.