Had a situation come up I can't find an answer for in the rules:

If a combat card ability asks my opponent to destroy a unit to gain a benefit (or prevent myself from gaining a benefit) can this unit be a routed unit?

I know routed units can't be assigned damage during the normal assessing damage step of combat, but I wasn't sure if this would count as that step as damage isn't really being assigned, just 'destroy or don't destroy'.

Edit: Forgot the whole title of the thread. My apologise.

If the text doesn't say otherwise, any unit is fair game.

Yes, you may choose to destroy a routed unit in that type of situation.