could be
Also check the battery connections to make sure they are not gunked up with corrosion. You sometimes have to look carefully because the terminal itself is fine, but the heavy cable going into the terminal can also turn green (copper oxidation) and conduct poorly.
It's certainly one of the two, and it sounds more like a connection problem than a bad battery since you can let it click, then sit, and then it will crank. A bad battery won't recover enough to crank if it doesn't have cranking amps when you first try.