Shoot, this is how I recapture our dog when he gets loose. Chasing him is no good, he thinks that's a game, so I just collapse on the sidewalk and yell for him to come help. He trots right back over to me.
Last time he went for a run I had to get the car! Found him playing with some kids at the local sports ground - I'm glad greyhounds have such a pleasant nature, and love people so much, because if he'd appeared any more aggressive than a giant and playful puppy, there might have been problems.