I agree we have no choice other than 'between' in the case of two defenders. But as for the case there are more than two defenders, I think we can choose both 'among' and 'between'. OED says about the choice as follows.
In all senses, 'between' has been, from its earliest appearance, extended to more than two. In OE. and ME. it was so extended in sense
As you see, I'm a mere learner. So I cannot tell you anything with confidence. What I can say is something I found in written documents or the result of google survey.
As for "difference between/among (the) three", the google gives: difference(s) between (the) three … 126,000+208,000+24,000+21,000=379,000 difference(s) among (the)