Pot Committed is a highly overrated concept.

[viennagreen]

i don't think you have to have a large portion of your stack involved to be "pot committed".

it just means that you are committed to the pot. Say you are big stack and big blind. short stack has 2BB's left--- he knows that you will call his all-in for only 1BB more, because you're pot-committed--- there's nothing in the world that you would fold.