Mansfield-born Clarke saw his side struggle during the opening weeks of the season, winning just one of their opening eight league games.
However, after earning a draw with Colchester United and suffering a narrow defeat to Bradford City, the Saddlers won three games on the bounce easing many of their relegation woes.
Darrell has been nominated alongside Dave Artell at Crewe Alexandra, Forest Green Rovers chief Mark Cooper and Cheltenham Town manager Michael Duff.