Waimate businessman Gary Rooney has agreed in principle to fund the cost of a second multi-purpose court for Waimate's stadium upgrade.
Mayor Craig Rowley said he was "very pleasantly surprised" by the offer.
Rooney initially made a funding offer when the council was hearing submissions about the stadium.
The Waimate District Council had previously planned for a single court stadium to prevent the costs to ratepayers exceeding its maximum target of $3.8 million.
That court would have allowed the sports played at the present stadium - basketball, indoor bowls and badminton - to continue.
The addition of a second court would also allow for indoor cricket, netball, football and tennis to be played across the two.
"Mr Rooney's got right behind the community," Rowley said.
He believed the $3.8m maximum council contribution was now "locked in", although final costs for a two-court stadium had not been established.
Rooney had "agreed to take full responsibility for the project build" to ensure that the council did not bear any potential cost over-runs.
Rowley said further details of the "fantastic deal" and plans for the stadium would be finalised in coming weeks, after the stadium's users were consulted.
It had been agreed that Rooney would have naming rights to the stadium, but it was not yet clear whether he would exercise them.
- The Timaru Herald