If Lampard sees a role in defence for Patterson I'd be alarmed at Lampard's judgement. Thus far he's made sure he's played him not as a defender and not as a wing back. He occupies some space between playing as a wing back and an out and out front player wide right.
It is the strangest phenomenon I've seen. It's like a half-position which can maybe pay dividends against sub-PL teams, when it's pretty much attack v defence, but not against the vast majority of PL teams when the competition will be tough.
You can play wingback a number of ways though someone like TAA is a rubbish defender - not saying Patterson is though, but TAA is considered one of the best wing backs out there.
You can even look at Combo's you can have one who is an extra attacker and one more defensively minded, like say Alonso and Azpi at Chelsea when they play, maybe even Patterson and Myko, i think Myko is a natural fullback with some skill in getting forward. The more defensive one drops deeper quicker to sometimes make a four if there is a breakdown.
It depends on the balance, if Patterson gives incredible width and threat in the final third and is clocking up assists because he has a cross on him, then your balancing up what he gives you in threat compared to what you loose with him defensively Vs Coleman. As it should be really, competition, options and variance in the squad. Especially when you a player of Bens profile who can compensate behind. We are a bit tame down the right hand side and this lad maybe could contribute in threat and output - if he proves it.