In a recent preseason friendly soccer match from the UK between Newcastle United and Fenerbahce, Newcastle United defender Davide Santon accidentally knocked down a security guard while chasing a loose ball near the sideline.
It occured in the second half as the wet field caused Santon to fall on his back and slid into the steward, who was facing the stands just outside the sideline. The security guard took an accidental kick in the back from Santon before being fully taken out from behind, but he fell on top of Santon, so that seemed to even things out.
The security guard got back up quickly, and although he appeared to be a little sore from the kick in the back, he otherwise appeared to be OK.
H/T Dirty Tackle.