If selected by coach Michael Bradley, Walker would become the sixth European debutant for the Gunners this season but the youngster insists lessons have to be learned from the 42-20 defeat to the Ulstermen.
He said: "Obviously my try is one of the memories I take forward, even if my line-out work needs a bit of attention since there was one overthrow and a couple of technical errors.
"We have no choice but to take on board what happened and move on from Ulster. Unfortunately we were not firing on all cylinders and we will do our analysis, as always. Everyone has bad days. It is now about re-grouping.
"But just to be in the squad watching from close range as Fordy (Ross Ford) goes about his business is a learning experience for a hooker like me.
"I'd love to help achieve the win over Metro. We are now just focusing on the Heineken Cup after we had a reminder of what is required from an Ulster side who reached the quarter-finals last year."
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