The NBA preseason is supposed to be a relaxed warmup before the season gets going. The last thing you want is a player getting hurt during the action. But things didn't go that way during the preseason tilt between the Golden State Warriors and Denver Nuggets.

Draymond Green accidentally rammed into Austin Rivers while trying to contest his shot. The Warriors star's knee inadvertently nailed Rivers right in the ribs, which had him laying on the ground in a lot of pain.

But thankfully, it seems as though Rivers' collision with the Warriors star just knocked the wind out of him. He appeared fine later on in the game and Draymond even apologized to him about the incident. But that didn't stop him from getting assessed a flagrant foul for his infraction.

Via Warriors beat reporter Anthony Slater:

Draymond Green flying knee to Austin Rivers ribs on a late transition contest, after arguing a non-call on the other end. Rivers was down for a bit, but appears fine. Looks like Draymond apologized to him at the FT line.

Hopefully the Nuggets guard gets a clean bill of health when he gets his ribs checked after the game. If not, you better believe Draymond Green is sending a gift basket to ease the pain.