Why is a level 3 obvious bronze player in a silver/gold rank game?

Just a rank game. Enemy team has a gold and the rest are silvers, our team has a level 3(according to opgg), and play like a bronze 5 or new player for sure, the rest of our team are silvers. That new player just 0/6/0, and down 104 cs in 15 minutes, wtf is this riot?