The winger has missed the last two games with a hamstring injury that forced him to come off early in Albion's 2-1 win at Old Trafford.
"Scott won't make Saturday," said Clarke. "He's progressing well but as it's a muscle injury we're just being a little bit careful. He's definitely out for Saturday.
"The ones who have been out for a little while, George Thorne and Zoltan Gera, have little niggles from the U21s game on Sunday. We'll go carefully with them.
"Everybody else is fit and available."