Eels coach Daniel Anderson admits he is alarmed at just how badly young playmaker Daniel Mortimer has been struck down by illness.

Mortimer was a shock withdrawal from the Eels' NRL loss to Wests Tigers last Friday after suffering from severe gastritis.

Anderson said he returned to training on Wednesday after being bed-ridden for four days.

"He's lost a significant amount of weight and he really can't afford to lose that much," Anderson told AAP.

However despite his weight loss, Anderson says he is confident the 20-year-old will be able to pull through and overcome his bad health by Saturday's game against the Sharks.

"The eyes were brighter and there was a bit of zest and cheek," he said.

"By Saturday he'll be fine."

Mortimer's direction in attack and tenacity in defence was sorely missed by the side last week, going down 23-12 to the Tigers.

Anderson said he was constantly astounded by Mortimer's effort on the field and whether he intended to or not, often put his teammates to shame.

"He plays above his weight and maybe he doesn't mean to embarrass his teammates but, with his style, he does," Anderson said.

Also looking forward to Mortimer's return will be plenty of concerned female fans, according to Eels captain Nathan Cayless, who says turn out more often when he is on the paddock.

"He's a good-looking bloke, who does rate his looks, and he should increase our female fans," Cayless said.

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