The A-League's most experienced player, Matt Thompson, has vowed to do everything he can to make sure his stint with Sydney FC lasts longer than three months.

The veteran midfielder was signed by the club as an injury replacement for Peter Triantis (osteitis pubis) just 10 minutes before warm-up for Friday night's season-opening 2-0 win over Newcastle.

The 31-year-old was on the lookout for a new team after being released by Melbourne Heart at the end of the 2012/13 campaign.

But the man who holds the A-League record for most appearances with 204 games to his name may again be without a club in January 2014, when his short-term deal with the Sky Blues expires.

"So I've got to do as much as I can in that time," he said on Tuesday.

"It's not an ideal situation, in that you're finishing up before everyone else, but that's the situation.

"I'm grateful for the fact they've given me a chance and I'm going to try and take it.

"To be honest, the plan is to try and play for a lot more than 12 weeks, so we'll just see how that goes."

The former Newcastle Jets star has been training with Frank Farina's squad for the past three weeks and said the team had welcomed him with open arms - especially former teammates Nick Carle and Richard Garcia.

"It's been great. Obviously being a Sydney boy it's been a bit sentimental in terms of being back home and all that sort of stuff," he said.

"I've fitted in straight away ... it was an easy transition.

"The club definitely wants the best out of everyone and they want nothing but success and I'm happy with that."

Sydney FC face Brisbane Roar in round two at Suncorp Stadium on Saturday.