I know you know that the heat maps aren't always useful for observations like that. Our wide players are going to look pinched since they flip side to side.I'm not sure lineup matters anymore, we play so fluid. But McNamara ended up playing the most in the middle last week, despite Mendoza technically starting there, according to the heatmaps on whoscored.com.
By the way, if it wasn't obvious before (there's been a lot of bickering about Lampard shirking his midfield duties), it's pretty certain that Vieira has quietly shifted us to a 3-3-4 system that he hinted at trying way back in ~May.
Two things to notice here. (1) McNamara played even with Villa over the course of the game. It is clear that there are four players up top that, at best, only occasionally drop back into midfield duties. (2) Matarrita played higher than Iraola and Pirlo. He's a midfielder that tracks back a little extra to shift us to a 4-man backline when needed. This also makes clear why Hernandez is playing over Allen. His spot is as much or more RCB as it is RFB.
My lineup for Houston:
F: Harrison, Villa, Shelton
M: Pirlo, Iraola, ^McNamara
D: ^Matarrita, Mena, Brillant, Hernandez
^Indicates the player is often playing up a line.
I agree that t Mac was doing most of the heavy lifting in center mid, as he's been doing for a while now.