Yeah, Mascherano is a world-class defensive midfielder. I never understood why Barca kept using him as a central defender (I have posted at least 5-6 questions about Barcelona misusing Mascherano as a central defender on the Spanish football section for the past 3 years now). It's because at Barca, Busquets gets picked over Mascherano in defensive midfield due to Busquets fitting into their style of play more. Therefore, Mascherano can only play as a center-back at Barca. Mascherano may 'get by'/do OK as a CB but he's truly world class as a defensive midfielder (his terrific performances at the WC were all as a defensive midfielder).

yeah

He has peaked now but he was almost world class for a couple of seasons with Liverpool

yes mascherano a world class player

Yes...

No, not since the shift to Centerback.