"It's always sad when someone, at 34 years of age, playing as well as he did, gets a severe injury like that,'' Merrick said. "It's a tough time to receive that type of injury, so he'll come good but I don't know exactly what the diagnosis is.''
It didn't look good on first viewing as Ifill crumpled to a heap on the floor without anybody making contact with him and he immediately signaled to the bench for help.
Aside from his ability on the field, Ifill is a strong character at the club and has been a consummate professional this season despite not always being in the starting XI.
With the worst confirmed, Merrick may look to bring in a replacement player, but that wasn't on his mind as he pondered the first win of the season following six losses and four draws to start the campaign.
"I haven't thought that far forward yet. We've got a team. We've got a squad. I feel as though we've got more depth in the squad now. I can bring players off the bench and they do a job, they don't just fill in. They actually do a good job.
"They keep going forward, we are all in the same sort of mould of style of play now ... The January [transfer] window still is what it is. There might be an opportunity to bring someone in provided it's the right person.''
The only goal of the game tonight came in the 33rd minute when Huysegems combined nicely with midfielder Carlos Hernandez to finish from an acute angle.
Huysegems' strike had certainly been coming and the Phoenix, as they have all season, created a stack of chances and probably should have finished with a greater margin of victory.
But Merrick will take plenty of heart from the fact his side dug in and ground out the result, while the players will have received a much-needed dose of confidence after copping a collection of frustrating losses or draws this season when they were the better side.
A crowd of only 6813 were on hand for the contest but the Yellow Fever were given the rare opportunity to remove their shirts as they traditionally do when the Phoenix are in the lead come 80 minutes.
There were some hairy moments in the final 10 and Huysegems should have doubled the advantage in the dying stages but Wellington did enough to hold on.
After Christmas the Phoenix head to Melbourne - a city they have never won in - to meet the winless Heart on Friday night.
Wellington Phoenix 1 (Stein Huysegems 33)
Sydney FC 0 Halftime: 1-0