There was surprise from some national team supporters when the 24-year-old was named in the squad for the 2022 World Cup qualifiers against Moldova and Denmark, on account of his return of one goal in 11 games for club and country but Clarke insists the forward is a quality player regardless of form.
"Kevin is a good striker,” Clarke said ahead of the trip to Chisinau to face Moldova.
"He'll be a good striker whether he's out of form a little bit, or back in form.
"Kevin's been good with us since he came into the squad. People go off the boil sometimes. Not everyone will be at their top level all the time.”
Nisbet and his Easter Road colleagues have lost their last four league games, with a Covid-19 outbreak at the club forcing the postponement of matches against Ross County and Livingston.
While the Capital club hasn’t had its struggles to seek, Clarke is of the opinion that Nisbet and his team can turn things around.
"Hibs have had a tough time of it in the last few weeks. They had a great start to the season and then maybe tapered off a little bit,” he continued.
"Jack [Ross] will be looking for some positive results and Kevin, as a striker, thrives on goals.
"Kevin played against Moldova the last time and was involved in the goal.
"If he's picked for the game he will be happy enough and do well. I have no worries at all."