He's been thrown under the bus at times during the season by Lucho who played him at LB. He got absolutely no business playing there, and we already saw that in Lucho's first El Clasico which ended 3-1 to RM. At CB he is very, very solid. I remember just from this season when Vermaelen was having an absolute horror show away to Malaga and Lucho subbed him off for Mathieu. The game changed completely. Anyway, a LB back-up is probably one of our main priorities in the summer, so we have hopefully seen the last of Mathieu at LB.