Jarryd Hayne is in doubt for Gold Coast's vital NRL clash with Penrith due to a calf injury.

Hayne injured his calf in last week's win over Newcastle and will be forced to pass a fitness test at training on Friday before confirming his place in the side.

Sidelined: Jarryd Hayne. Credit:Getty Images

If Hayne is out, David Mead would likely slot back into the Titans fullback role for Saturday's game.

Meanwhile, having shared the 2014 Dally M Medal with Hayne, Johnathan Thurston is fully aware of the threat his former Kangaroos teammate poses to North Queensland's top-four aspirations.