Confirmed by Lindsey Tucker. On WBN site.
http://www.worldboxingnews.net/news.../news/2014/06/06/shawn-porter-v-kell-brook-agreed-for-august-9-in-new-york.html
http://www.worldboxingnews.net/news.../news/2014/06/06/shawn-porter-v-kell-brook-agreed-for-august-9-in-new-york.html