Doesn't really have to be though. We just need a cheap, decent enough back-up option for the only left-back in the squad that is actually good enough (and let's face it the jury could well still be out on Myko).
Vinagre is 23, will be happy to fight for his place and gives us an okay rotation option. Weirdly, one that is actually a proper LWB, as opposed to the more defensive LB that Myko is (but I think Myko is still the better player).
That's all this is. The wages are reportedly around £16k a week, and Lampard and the coaches have decided Nkounkou isn't ready. He's only got 12 months left so will likely be moved on. If Vinagre does well in his year here, then we have a deal agreed if we'd like to sign him.
Yes, it wasn't an absolute priority, but it's a deal that's costing a relatively tiny amount for a position that did need addressing at some point this window.