Has Sammy Hagar Joined Tool?

Is Sammy Hagar joining Tool? Maybe. The band posted a photo on social media this weekend of Sammy and Maynard together drinking wine with the caption: 

"In an effort to nudge the things forward in what seems to be an endless music writing process," the caption of the photo reads, "Maynard James Keenan has enlisted the help of Sammy Hagar to temporarily replace him as the vocalist for the slow moving internationally recognized rock monster truck, Tool."