A little math:
Let's pretend Ward rebounds to post a .910 save percentage (career average). Let's also pretend the defense somehow becomes league average, and they allow exactly 30 shots per game (down from 30.8 last year). Finally, let's pretend Ward plays exactly 40 games worth of minutes, through starts and in relief of Khudobin when he has an off night.
That means, in 2400 minutes, he'll face 1200 shots. Stopping 91% of those yields 108 goals. If Khudobin starts the other 42, facing the same frequency of shots, and stops 92.8% (his career average), he'll allow 91 goals.
199 goals would rank 8th best last year, and 27 fewer than they actually allowed. They shave off roughly one goal against every three games.
Sounds good, but it assumes a lot:
-Ward will rebound enough.
-Khudobin won't struggle in any way.
-Neither will get hurt.
-The defense will allow fewer shots.
This is probably a best case scenario, and they're paying 6.7 million for it.