The 19-year-old has only made three appearances for the Saddlers this season, all in the EFL Trophy.
He struggled in the opening two before marginally improving against Oxford United last week and although Clarke believes he is improving, he still wants to see more.
"He's only a second year pro and he has to perform better than he did in the two Trophy games," Clarke said.
"He had opportunities and didn't perform anywhere near to the standards we set him.
"To be fair to the boy, he's knuckling down really well in training. We've got some weight off him as well – he needed to lose a bit of weight.
"We're getting him stronger and he needs to take his next opportunity.
"With younger lads they don't get as many opportunities as the senior boys but it's back in Jack Nolan's court when he plays and when he comes on.
"We'll keep working away with him and hopefully he takes those opportunities when they come."
With Josh Gordon injured, Walsall have a gap to plug on the right wing with Rory Holden regularly filling it – despite being better suited to playing behind the striker.
As Nolan is still to get up to speed, Clarke admits they're still trying to fill Gordon's void, but also believes they have had no problem creating chances.
"Holden is good as a 10 and Nolan is not quite to the levels I expect him to be at the minute.
"To be able to have that option is something we're looking at, to fill the void.
"Let's be honest, the majority of games we've been the better team but we're not winning games. We're not being ruthless.
"Fans will be sick of me saying that but at the end of the day have we created enough chances in most games? Yes we have.
"Have we created enough chances to score two or three goals in most games? Yes we have.
"We have to take those opportunities and defend better."