Goalkeeper Walker was outstanding in only his second Premiership start of the season against Southampton on Saturday.
He kept the Saints at bay with four fine saves in the first half as a scrappy encounter ended goalless. The former England international will now look forward to Upton Park as Sullivan sits out the second of his two-match ban.
And the big question is, if he plays well against the Hammers, will he hold onto his place? Walker insisted: "That’s not for me to answer, it’s for the manager to answer.
"We’ll see how it goes against West Ham. I haven’t got a lot to lose there, I’ll just try to go out and do the best I can and at least then I would have given the boss a question to answer."
Walker saved well from James Beattie, Hassan Kachloul and Kevin Davies to clinch the man-of-the-match award and praise all round from his team-mates.
He added: "The game went as I imagined it would go. It went really well and to keep a clean sheet was what I was after really.
"I was pleased. It was just a shame we couldn’t get a goal at the other end but for me, to keep a clean sheet was what it was all about.
"Southampton are a big strong side but we had a lot of youngsters playing, Les got injured early on and that made it difficult.
"We didn’t get the ball down as we could have done but it wasn’t really one of those games. It was a battle out there and I thought we defended pretty well."
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Ian Walker is determined to leave manager George Graham with a dilemma when Neil Sullivan’s suspension ends after the derby at West Ham on Wednesday week (January 31).