very large stack on the bubble with a very small stack that folded

[reubenf]

This is from a two table tournament I played on stars today (I assume this forum is okay for that?). I don't have the hand history, so I'll have to do this by memory.

Blinds 200/400 with a 25 ante.
UTG with 215 chips.
CO with 4k chips.
Button (Hero) with 20k chips.
SB with 1.5k chips.
BB with 1.5k chips.

CO is usually pretty solid, and has been minraising to get the blinds when I'm the button pretty often.

UTG folds, CO minraises, what kind of a hand does Hero need to push? I should note I haven't pushed preflop at all this SNG.