I imagine he'll be a nailed on starter. How are his crosses?
His crossing is average, I'd say. He used to have a great engine (he's 31 now, so we'll see if he still has that) and by all accounts is a solid defender. He's not a flashy player, really, but very dependable.
To be very honest, I don't think Janmaat's attacking side has looked all too great since flashes in his first season with us. He was very aggressive hitting driven balls and taking shots early-on but later on felt he was somewhat overrated going forward.