ESSENDON coach James Hird has again overlooked ruckman Jonathan Giles because he didn't want to drop Shaun McKernan after one poor game, despite the club's ruck troubles.

McKernan was soundly beaten by North Melbourne ruckman Todd Goldstein last week in a match-up that Hird said was the difference between the sides.

Giles performed well at VFL level the next day, recording 29 hit-outs, kicking two goals and showing more around the ground, but has failed to break through for his first senior game in Essendon colours after being traded to the club last year following three seasons with Greater Western Sydney.

The recruitment of Giles and his continual non-selection has been puzzling, given the Bombers' issues in the ruck and a long-term injury to Tom Bellchambers.

But the Bombers have resisted picking Giles for Saturday night's clash with Port Adelaide at Etihad Stadium, instead choosing McKernan to shoulder the load against Power duo Paddy Ryder and Matthew Lobbe.

"I don't think it's about Jonathan, it's more about Shaun. I don't think that after one performance when you get beaten that you throw a player out," Hird said on Friday.

"I think Shaun's brought something to the team which has been good and I certainly don't believe that you throw a player away and go and get another one just on one performance. Shaun's got an opportunity this week and we hope he performs."

Match preview: Bombers v Power

Giles signed a two-year deal last year that goes through until the end of 2016, and despite his inability to win a senior spot, Hird said the 27-year-old would remain at the club next year.

"Jonathan Giles is a contracted player, we want him to play, he's starting to play how we want him to play," Hird said.

"He played well last week and we hope he plays well this week and there's an opportunity there next week, who knows. He's a contracted player and we want him to keep playing well."

As Essendon's ruck problems mount, the Bombers will face Ryder for the first time since he crossed to the Power at the end of last year.

Hird said the club "certainly missed" Ryder's ability to have ascendancy in the tap work, with the Bombers ranked the worst centre clearance team this year and last for hit-outs across the competition.

Ryder this week admitted he was nervous about playing the Bombers, but Hird didn't think the Bombers would cross the line when facing their former teammate.

"I'm not sure whether players will get under his skin or not. We want our players to go and win the contested footy, defend well and use the ball well," he said.

"What happens on the field in terms of banter will be between good friends and hopefully they have some fun out there, but I think it will all be done in the right spirit."