The Welshman has been linked with a return to the Premier League, and Lampard has tipped Bale to depart the club on a positive note.
"No-one really knows what is going to happen with Gareth this summer," Lampard told Evening Standard.
"There has been a lot of speculation because, for one reason or another, he is no longer a regular in the side. I think there are a lot of things going on behind the scenes that perhaps we don't know about. Politics plays a huge part in Madrid, we have seen that happen before. But what isn't in doubt is Bale's ability to effect the game.
"He gives Real a width and a directness that they have lacked this season. I wouldn't be surprised to see him starting, but even if he only comes off the bench, Bale can cause Liverpool problems. If you look at how Liverpool defend, you want to have people that know how to run in behind and around the back of them. Bale can give you that.
"Gareth has been a huge success at the Bernabeu whatever happens. Should he decide to return to the Premier League, he can already bring back three Champions League winners' medals and it may be four come tomorrow. He has been a major factor in those victories, scoring in finals for them.
"Moving abroad, as Bale did for around £86m from Tottenham in 2013, has not always worked out for British players. But the way he has expressed his quality and developed as a star man, no one can dispute his contribution and that he has justified the move. Should this turn out to be his last game for Real, he will want to affect it in a positive fashion. People remember you for your finals and the medals. The list is next to your name forever and Bale has one to be proud of."
Follow the Champions League final live on Sports Mole by clicking here.