My theory Edit
Donovan is most likely knows Penny. Desmond told him the outcome of the soccer game, but he was one day early.
When Donovan hears the next day who won, he will remember what desmond said and most likely seek out penny and tell her what has happened. Maybe this leads to the series of events that leads penny to look for Desmond.
Daniel Donovan connectionEdit
I'm going out on a limb here but here goes. Desmond Hume and Daniel Faraday share a "mutual friend". Donovan and Daniel are physicists and I would be willing to bet both worked as tenured professors at Oxford University. When Desmond was in prison Donovan made the introductions between Penny and Daniel and they later became engaged.