The former England captain, who retired last year after a short stint playing in France for Paris Saint Germain, admitted he had "a tough time" after calling a halt to his career.
Appearing on the new BBC documentary David Beckham: Into The Unknown, he said he had gone through "a stage of enjoying the rest" but was now tempted to go back.
He said: "Now I go to watch a basketball game and, when you are watching athletes play at the top of their game, for me it gives me that itch again and I want to be back in the game then and I start thinking to myself 'Could I play again? Could I go back? Could I come out of retirement and start playing again?'"
Beckham is currently trying to launch his own Major League Soccer team in Miami and hinted he might turn out for them.
The former Manchester United and Real Madrid midfielder said: "There's never been a player-owner but maybe?"
The former footballer travelled 800 miles (1,287km) into the Amazon rainforest for 12 days to make the documentary which goes out at 8.30pm on BBC One next Monday.
He was joined by three friends to fly into Rio de Janeiro and then continue their journey by motorbike, canoe and plane to meet the remote Yanomami tribe and spend the night in their isolated village.