The former Fulham and Norwich City man, who has been deputising for the injured Kevin Muscat, believes the Costa Rican only needs one goal to get himself back in the swing of things following a fruitless eight matches thus far.
"In Carlos' defence, he's been amongst everything that we've done going forward, creating chances," Leijer said.
"One of those is eventually going to go in and he'll break his drought and then hopefully he can kick on from there and score a few more. I don't think it's as easy for midfielders to score goals with Carlos and his role there but as long as he's creating for us, we'll take that."
Hernandez's midfield mate Billy Celeski agreed with Leijer, saying that those chances created would soon be put away.
"I think we are keeping the ball fairly well in midfield, creating chances, moving the ball forward, trying to get Carlos involved as much as possible," he said.
"I think at times you are not going to be able to create five, six or seven chances in a game but if you create two or three, we need to be good enough to put those chances away and we've addressed that and the players know, they've put their hands up. So we're working hard on that."