According to Charlie Cook at the Cook Political Report, King has moved from the "Solid Republican" column to "Likely Republican." (opens a .pdf).
"Likely Republican: is defined by Cook as "
Sure, it's a small move but a significant one that shows King is vulnerable in a district dominated by republicans. For a race King has walked away with in recent years, things are tightening up.
Mejias is doing an outstanding job even with his late start.