The Mariners have always existed on a very tight budget and need to know how much the A-League clubs will receive in their annual grant from Football Federation Australia before they can make a concrete offer.
The club has not always been able to spend right up to 100 per cent of the salary cap and is currently spending at the allowed floor of 90 per cent.
If an increased grant for season 2017-18 is far enough above next season's salary cap it could allow the Mariners to spend to 100 per cent of the cap as well as adequately cover running costs.
But decisions on the size of the cap and how far above that the grant will be are still to be made while FFA waits to find out whether it can establish a free-to-air component to add to its new pay television deal.
That is expected to take at least another month and could stretch out to several months, depending on negotiations.
"We're in contact with Roy's agent, as we are with the majority of the players, and with them all we're really waiting to see what next year looks like in regard to the broadcast deal," Mariners CEO Shaun Mielekamp told The World Game.
"When we've got a bit more clarity with that we can progress those talks with him."
Irishman O'Donovan, 31, is midway through the final year of a two-year deal with the Mariners.
He was their leading goal-scorer last season, registering 8 goals in 19 games for a team that struggled to find the net overall, and is again on top for them this season, with five goals from 11 games. No other Mariners player has scored more than one goal this season.
O'Donovan is known to be happy at the club, but it is only natural he would want the team to be more competitive. The Mariners desperately need to keep him first and then use him to attract more players of similar quality if they are to achieve that ambition of becoming a force again.
"Exactly, and it's the chicken and the egg scenario," Mielekamp said.
"The challenge for us as a club is to clearly know where the cap is going to fall, and where the grant is going to fall above that, because the difference is absolutely critical to our long-term viability.
"Without knowing that it's difficult to really project our future."
Re-signing O'Donovan is obviously a priority and it will reach the point at some stage where the Mariners feel compelled to make him a definite offer regardless of whether the uncertainty over the grant still exists.
O'Donovan is bound to become a target for other A-League clubs and perhaps also in Asia if the Mariners aren't able to wrap him up soon.
He has been on target 12 times from the 23 shots he has had this season, ahead of Wednesday night's game against Melbourne Victory at AAMI Park, and also has one assist.
His goal-scoring efforts look even better when it is taken into account the Mariners have the worst percentage for crossing accuracy in the competition - just 17.2 per cent.