Popov joined the Baggies last month on-loan from Dynamo Kiev.
"Goran is under no illusions," said Clarke. "He knows he is coming in to fight for a place in the team and all the players now, after the start we've had, realise that they have to fight for their place in the team.
"As long as the competition is healthy then it can only be good for the club.
"If the team is performing well and getting results then the players not in the team will be disappointed but they're not stupid.
"They understand that they have to wait for their chance. And it will come because it's a long season."