The 27-year-old completed a switch to the Baggies last month on a season-long loan deal from Dynamo Kiev.
However, Clarke has warned Popov, as well as his teammates, that nobody is guaranteed a place in the starting lineup.
"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."
Clarke's side are currently third in the Premier League table.