The first rumblings of a serious Democrat to run against Senator Flake.  The calculations are being made for several people right now, as there are definite headwinds for Flake to win re-election, not the least of which is a strong primary fight on the Republican side.

http://tucson.com/news/state-and-regional/rep-kyrsten-sinema-seriously-considering-challenging-sen-jeff-flake/article_cab69b8d-ec5a-5680-8077-2c170b3e24dd.html