In-Game Leader-Boards not showing the players

Just had my tail handed to me by a Yasuo who got 25 kills against our team. So I checked the leader boards and didn't see him listed in either my division or the division above me.

A quick examination of his record from op.gg shows him listed as bronze V with hiis last few games all having kill counts ranging from 12~35.

So why is he not on the leader board for Bronze V?

(the referenced match: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2257602204/230329210?tab=overview )