So, Quadjumper has an action which reads, "discard this support to play a support from your hand, decreasing its cost by 3." It doesn't specify that you have to discard it from play (e.g. Honor Guard, "discard this support from play to remove a die showing damage"). Does that mean that you can discard it from your hand, as well as from play? There are some actions as well that state "discard this card from your hand," which leads me to believe that Quadjumper's action can be used either if it is in play, or if it is in your hand. Thoughts?

I would say no you can't discard it from your hand. I am no rules expert so take it with a grain of salt but I believe that an action on a support can only be used when the support is in play.

You cannot perform an action listed on a card that is not in play unless the card specifies that it can (See Cloud Car).

Ok, thanks! I agree with you both, I was just curious. It would definitely make Quadjumper the best card in the game IMO.