Kasim will sit out Monday's match in Sydney after picking up his second yellow card of the competition during Iraq's dramatic last-eight victory over neighbours Iran.
While Shenaishil concedes it is a blow to lose the Swindon Town midfielder, he remains optimistic.
"Yaser is a rising star in Asia and also in the Iraq national team," said Shenaishil.
"It's a disadvantage to lose this player but as a coaching staff we always think of losing a player to either injury or suspension so we always have to have someone ready.
"I think the player that has replaced him will continue Yaser's journey; hopefully into the finals.
"He will be a new player, nobody will know him, with a lot of ambition to produce something on the day instead of Yaser."
Shenaishil believes Iraq's recent fixtures have benefited the team as they prepare to face South Korea as underdogs.
"Korea is probably one of the best teams in Asia, [but] we've gained a lot of experience playing strong teams," he added.
"Before going to this competition we had friendly matches with Uzbekistan, we also had a friendly match with Iran and also another match during the competition and also playing Japan. So I think our players have gained enough experience to play against strong teams and to be at this level in the competition.
"Hopefully our players can produce something on the day so we can come out with a positive result for our country."
