By Daniel Chavkin The NFL commisioner explained the league’s potential motivation behind playing games overseas. The NFL returns to London for the second time this year as it continues its 14th season playing games overseas. In total, the league is sending four games to Europe, three in London and one in Munich, Germany, and that is by design. Commissioner Roger Goodell said he hopes to expand the league into Europe in the future, eyeing potentially four European expansion teams for a Europe-only division. “There is no question London could support, not just one franchise, [but] I think two fr…