Riewoldt suffered a minor ligament strain in his ankle in the loss to Fremantle last Saturday and will be kept to light duties this week.
Cotchin says he's recovered from the "dead arm" he suffered when he took a knock just above his elbow as he tackled Docker forward Hayden Ballantyne.
"I just went to tackle and somehow collided with Ballantyne's body in a way that made my arm go half dead," he said.
"It was really painful. I wasn't sure what was wrong with it.
"I thought it was a cork initially because I had no strength. I was a bit worried about it.
"But once it settled and I got back into the swing of things, it started to come alive again.
"It felt OK towards the end of the game."
Cotchin said the previously in-form Tigers let themselves down in key areas in the 12-point loss to Fremantle and know they must attack the ball harder against the young, but tough Giants.
"They're a really good contested team," he said.
"It's going to be pretty tough. We've got to make sure we're harder at the contest, unlike our performance last week."
Tigers midfielder Nathan Foley will also be monitored this week after missing the Fremantle loss with a bruised heel, while small forward Jake King is available after serving a one-week suspension.