The 19-year-old goalkeeper dropped the ball into the path of Reda Johnson, who fired in the opening goal of the match for Wednesday.
However, Clark believes that England international Butland has the ability to "bounce back" over the coming weeks.
"Listen, when you are a goalkeeper and you make an error, I would say nine times out of 10 the ball ends up in the goal and unfortunately that's what happened," Clark told reporters.
"I have no doubts that throughout the long career he will have there will be more. It's how you bounce back and how the people around you bounce back.
"It's just maybe a wake up call for everybody because the hype that has surrounded the lad the last few months, we have just got to put it into context."
Butland made his England debut during last week's 2-1 win over Italy.