Bosnar has been training with the Sky Blues for the past fortnight and could join the club for the remainder of the season after he was recently let go by Chinese side Guangzhou R&F.
The exit of Brazilian defender Tiago Calvano this week – coupled with the loss of fellow centre-back Pascal Bosschaart at the start of the season – has left Sydney a little short in defensive options.
And Bosnar would seem the perfect replacement, with Farina admitting the club will have to make a decision in the next couple of days whether to sign the 33-year-old.
"(Tiago's release) does open a door but whether or not we decide to welcome (Bosnar) through that door we'll decide most probably on the weekend," Farina told reporters on Thursday.
"Eddy's looking in good shape and we are looking a bit thin across the central defence now with Pascal (Bosschaart) leaving and Tiago as well.
"So there's an opportunity there but we won't make a decision until after the weekend."
The Sky Blues have two spots open on their roster with the possibility to strengthen their squad for an all-out assault on the championship over the final few months of the season.
But Farina is adamant he's not prepared to add just any player to his side just for the sake of it.
With the likes of Alessandro Del Piero, Ali Abbas, Richard Garcia and Terry McFlynn all off-contract at the end of the season, the Sydney boss is prepared to bide his time in shaping his squad.
"I'm satisfied at the moment. We've got two spots available now but options are the issue," Farina said.
"There's no point filling those spots just for the sake of it ... and we're travelling along fairly well with injury at the moment.
"If we fill those spots it will only be until the end of this year it won't be long term.
"At the end of this current season only eight players remain on contract so there's an opportunity to really rebuild."
Asked about the potential signing of Bosnar, who has spent the last 13 years playing in Europe and Asia, Farina said: "He doesn't have to do a lot (to impress me) ... he's got a great history.
"I haven't seen a lot of him because he's been away for 12-13 years but he's in good physical shape.
"It's just a decision we've got to make both financially and for the team. If it's the right one we'll go about it."
After going five games without a win before last weekend's remarkable 5-0 demolition of Melbourne Victory, Farina concedes it's too early to say Sydney have turned the corner ahead of Friday's clash with the last-placed Heart.
"Last weekend was great but we've got to find that consistency and try and back that up this week," he said.
"We've had two trips to Melbourne this year and both have been pleasant ones so hopefully we can make it a third one as well.
"Melbourne Heart have been through some difficulties this year but the last two weeks they've played pretty well. They are a good side and even though they are last on the ladder it's going to be a tough game."
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