INJURY has forced young utility Jason Johannisen out of the Round 19 clash with Port Adelaide this Saturday.

The speedy half-back has been withdrawn with hamstring tightness.

He’ll be replaced by key defender Joel Hamling, who’ll come in to bolster the Dogs’ backline.

Lukas Webb has been named as an emergency taking Hamling’s place.

Hamling has five senior games under his belt this season, with one being the Round 10 clash against Port Adelaide, starting in centre-back against Jay Schulz.