Thanks to the posters offering thorough assessments of Panik's play while he was on their respective home teams. We appreciate it. It sounds like he's decent (if streaky) middle-six guy with a good set of tools who is best suited, and most likely to meet all reasonable expectations, playing on the third line--which is exactly where Caps management plans to put him. He is straight-up our replacement for Connolly, our 3RW who was on a decent contract and had a great year in his contract year and priced himself out of D.C. If one of our top-six RWs get injured, Panik could possibly step up for a bit, but likely with less satisfying results. (Connolly did the same thing.)
As long as chemistry with Eller/Hags develops, it sounds like Caps fans will be relatively happy with this acquisition.
As far as that fourth year: Like several Caps fans with knowledge of BMac's signing strategy have stated, he has a penchant for low-AAV, extra-year contracts. You can essentially view this as a three-year contract with an option year (in which he gets traded if the Caps don't want him for that fourth year).