Will Sunderland fall to defeat in their first game under Sam Allardyce?
The former Arsenal, Aston Villa, and Portsmouth midfielder believes this is the biggest game of Sunderland's season so far, and a tough one for new manager Sam Allardyce to triumph in.
Merson paints a bleak picture if Sunderland lose, but feels West Brom will have too much for the Black Cats, predicting a 1-0 win for the home side.
He said: "This is a cup final for Sunderland, a must-not-lose. If they lost this, you're probably talking about having to win three matches to get out of the bottom three, and we're only eight or nine games in. That's a big, big ask.
"West Brom still have that bit of cutting edge, and I think Sunderland will go there and shut up shop and go for a 0-0, but West Brom will break them down."
While Allardyce has been brought in to save Sunderland's season, he goes up against a manager who is as wily as he is in Tony Pulis, who arrived at West Brom in similar circumstances earlier this year.
Merson's comments sound dramatic, but the Premier League table does not lie. Sunderland are in 19th and West Brom 17th, yet there is already a five point gap between them, which will extend to eighth with a Baggies win.
West Brom will be approaching the game knowing that this is an opportunity for them to pull clear and get a bit of belief, with even a draw being a solid result as it keeps a healthy advantage over Allardyce's side.