MITCHELL PRENTICE may be quiet off the field but again he's ready to do his talking on the pitch as Sydney FC's inexperienced back line prepares for a three-pronged assault from Central Coast Mariners tonight.

Lost in the attention focused on rookies Beau Busch and Antony Golec in last week's triumph in Melbourne was the role played by the versatile Prentice, who arrived in the off-season from Perth Glory ostensibly as a midfielder, but who was also viewed as defensive alternative by coach John Kosmina.

Two red cards (one in the pre-season) and a niggling injury stymied his initial impact, but Kosmina turned to Prentice for last weekend's tough Telstra Dome road trip, and was rewarded with a mature contribution as the defensive organiser. A clean sheet against the competition's best attack was an unexpected bonus, as well as a confidence boost for a spare parts back line that has been further depleted tonight by the untimely injury to Robbie Middleby.

Middleby will be replaced by Shannon Cole at left back - meaning Sydney's back four will have just 15 appearances between them this season. It's a challenge against a Mariners attack boasting three natural strikers - Dylan Macallister, Matt Simon and Sasho Petrovski, but Prentice is ready to take the responsibility.

"Obviously it's going to be a hard game. It's not just their front three you've got to worry about, it's the fact that they're non-stop for 90 minutes, and they're a very hard team to break down," he said. "All three of their strikers can be a handful. They can all turn the game on their own, so we definitely have to treat them with respect. But we can do it, definitely. There's a good buzz in the team at the moment."

Part of that spirit has been generated by Kosmina's willingness to reward players on form, rather than reputation, and Prentice - effectively deputising for injured skipper Tony Popovic - is determined to make the most of his opportunity. "Playing at the back, it's a role I've played before, so I know the duties that have to be done," he said. "I may be pretty quiet around the change room, but once I get out on the park, the job has to be done, especially in that role. You need to organise. Last week I think the boys responded quite well. I was pretty firm with them on certain occasions, but they did their job and helped the team out. I'm sure we can do the same thing again."

Meanwhile, Mariners skipper Alex Wilkinson has re-signed for two more years. One of 10 foundation players at the club, the 24-year-old defender said: "I'm delighted to have extended my stay … the atmosphere and culture here is something very special and it was always my absolute preference to remain on the Central Coast."