Chris Hansen's group attempting to bring the NBA back to Seattle has made a proposal to renovate KeyArena into a mid-sized concert venue.

The plan would split KeyArena in half by creating a 6,200-seat indoor concert venue on one side and a 3,000-seat outdoor covered amphitheater.

Hansen is attempting to build an arena in the SoDo area of Seattle.

Hansen’s group said the KeyArena re-development would occur after a SoDo arena is built. Hansen’s group estimates the cost to be between $90 million and $100 million.

“We believe these new venues would be a perfect complement to the larger SoDo Arena’s 16,000-21,000-seat flexible capacity,’’ Hansen’s group said on the website. “It would also address the City’s need for a mid-size concert venue and amphitheater. We believe the combination of a completely new and modern SoDo sports arena and the new Seattle Center Venues is vastly superior to a single, site-challenged sports venue at KeyArena.’’

Tim Leiweke and Irving Azoff are offering to renovate KeyArena for the NBA and NHL.