Arizona Cardinals star wide receiver DeAndre Hopkins is looking for answers after a questionable moment during Sunday’s loss to the Minnesota Vikings.

The five-time Pro Bowler took to social media on Sunday to ask the NFL for an explanation following a violent helmet-to-helmet hit he took in the end zone, late in the third quarter.

Hopkins was walking back into the end zone, attempting to catch a short pass from Kyler Murray when he was tackled by cornerback Cameron Dantzler. After the ball fell from Hopkins’ hands, safety Harrison Smith seemingly leaned in for a hard hit, making contact with his head.