As the Phoenix trained in bright sunshine at their Newtown Park base today (fri), Fenton was doing his own sprints and ball work but the bigger concern was around Sigmund who is battling a groin ailment.
The 31-year-old has formed a solid defensive partnership with skipper Andrew Durante at the heart of the Phoenix back four in recent seasons and his withdrawal would be a big blow.
Phoenix coach Ricki Herbert hoped to be able to call on Sigmund for the game but would make a decision tomorrow (sat), with Michael Boxall forming a ready-made replacement if required.
"We'll just give him that extra time till tomorrow and hopefully he'll come through it," Herbert said of Sigmund.
"Louie's young, I'm sure that adrenalin will go through his body and hopefully he'll be okay as well."
Fenton has played from the pine in recent weeks but if he was to be scratched the door would swing open for Dani Sanchez to be included in a match-day squad for the first time this season.
The Spaniard has been on the shelf for an extended period with a knee injury but got through a decent shift for the Phoenix reserve side against Waitakere United during the week and would add useful diversity to the bench for Herbert.
Sanchez produced flashes of brilliance for the Phoenix last summer when he was deployed in the centre of the midfield but was less effective when he played out on the left towards the back end of the season.
In other injury news, goalkeeper Glen Moss will undergo surgery next week to treat a sports hernia and the expected recovery time is seven to 10 days so the All Whites custodian should be back on deck in two weeks.
Sydney FC have injury concerns of their own after marquee man Alessandro Del Piero was ruled out of Sunday's game with a hamstring problem.
The Glamour Club of the A-League currently sit at the bottom of the ladder and are now under the guidance of former Australian national coach Frank Farina.
The Phoenix comfortably disposed of Sydney 2-0 during the opening round of the season in October but Herbert said Sunday wouldn't be a guaranteed three points despite the Sky Blues' woeful form of late.
"The side's probably a little bit different than we had in the first round. But, look, I think like any side in the league I'm sure their expectations are to be at the top of the league not the bottom so they'll be hungry. But our form's good too so we've got to keep going and hopefully we can get another three this week."
The Phoenix are unbeaten during their past three games and brushed aside the Western Sydney Wanderers 1-0 in Wellington last weekend but Herbert said he wanted his side to be more clinical in front of goal this weekend.
At the end of training today Jeremy Brockie, Tyler Boyd, Paul Ifill, Vince Lia and Alex Smith all put in an extensive amount of shooting work and Herbert will hope that comes in handy on Sunday.
