First I'd echo
@Boss_Blue and say hands off our Seamus!
He came on a lot last year imo on the defensive side of his game - he used to be a touch hot headed, although not as much as Rafael, but he's matured quite a bit. Strangely Bolasie seems to cause him more problems than Hazard has, perhaps speed? Seem to remeber Evra having more bad games with a Spurs winger (Lennon?) than he did against wingers typically rated higher. Doubt he'll ever be quite as good as say Ivanovic on the defensive side but when he is on form that is compensated at lot by his attacking output, especially if you have a midfielder who can cover for him when he gets forward.
His hamstring injuries are a touch concerning, not having the partnership of him and McCarthy in many games has been one reason for our poor form this year imo.
Was very surprised given Rafael's injury history you didn't buy a RB in the summer, especially as you don't seem to have any academy players in that position either. That is why I mentioned Chambers tbh, though he might have made a decent stopgap as although he might not be as good as Shaw I would have thought he was better than an out of position Valencia. Your other backups of Jones/Smalling have had quite a lot of their career stunted by being shifted out there and they are just a likely to be in the physioroom as Rafael!