Matthew was caught by a Stephen Wright challenge on Saturday and was carried off on a stretcher before going to a local hospital for X-rays.
The incident had a hugely detrimental effect on West Ham's performance that, arguably, cost them the game - along with the loss, pre-match, of David Connolly with a thigh strain.
There is something of a sense of relief from Matthew, though, that the diagnosis isn't worse.
"It is a little bit sore but at least it isn't broken - it is just bruising," he says.
"It doesn't look like I will be okay for Wednesday, though it is more likely for Sunday.
"It wasn't the best of tackles; I saw his studs coming towards me so I rode it to some extent."
Is he being targeted by opposition defenders?
"I am a little bit," he admits, "but that is something I have to deal with and get on with.
"I thought I had broken my leg because I was in a lot of pain, and I still am, but I am just glad it isn't what I feared."