MELBOURNE, AUSTRALIA - AUGUST 21: Jack Hombsch of Port Adelaide is chased by Paul Puopolo of the Hawks during the round 21 AFL match between the Hawthorn Hawks and Port Adelaide Power at Etihad Stadium on August 21, 2015 in Melbourne, Australia. (Photo by Robert Cianflone/Getty Images)

Port Adelaide has suffered a blow ahead of Showdown 42, with defender Jack Hombsch ruled out of the match with a knee injury.

The 24-year-old, who has played 62 games for the club, will miss the match due to a medial ligament injury.

He sustained the injury during the closing minutes of the side’s big win over the Dockers on Sunday evening.

The Power are also sweating on the fitness of Robbie Gray, who is battling groin soreness.

Meanwhile, the Crows also have injury concerns, with Josh Jenkins racing the clock to prove his fitness after he was hospitalised on Saturday with a rib injury.

Jenkins was cleared of any serious damage but still has heavy bruising. He was restricted to walking laps at training on Wednesday.

He is expected to be named in the 22, but is no certainty to take his place in the side.

The Power hold a slight advantage in the head to head between the two teams, leading 21 wins to 20.