On April 12, 2014, the Golden State Warriors purchased a 12-acre site in Mission Bay from Salesforce to build their new arena. Previously they were trying to build their new arena on Piers 30-32, but decided to buy this area instead when they experienced opposition to building there and also because of the cost of restoring the piers.
In an article about the plans, CurbedSF writes: "It's all hearsay, but we're sure Salesforce was eager to offload the site to the Warriors since it just inked the biggest commercial lease in San Francisco's history as the Transbay Tower's anchor tenant."
CurbedSF covers this building project at http://sf.curbed.com/places/warriors-arena.