The proposal by Microsoft CEO Steve Ballmer to expand KeyArena is no longer an option, the Seattle Times are reporting.

Ballmer had originally put an April 10 deadline on the offer to pay half of the $300 million KeyArena expansion needed to keep the Sonics in Seattle, but funding for the other half fell short, according to Seattle Mayor Greg Nickels.

"This is a truly missed opportunity for our city, the region, the state, and the NBA," Nickels said.

Nickels vowed to try to keep the NBA in Seattle.