Potbelly's is on the northside of the center pier where US Airways and American gates 23-34 are located (sometimes called the B/C concourse).

There's a shuttle van that runs from near gate 25 on the B/C concourse to near gate 38 on the C concourse. You won't have to re-clear security if your flight departs from the C concourse after grabbing a bite from Potbelly's on the B/C concourse.