Does Teemo Strategist's 'when I defend' ability trigger when revealed from hidden state as a reaction, even if no combat is occurring?

Ruling: Teemo's "when I defend" trigger only activates when he is flagged as a defender in an active combat. He does not trigger simply by being revealed from hidden state outside of combat.

Sequence:

• Teemo must be defending in an active combat to trigger
• The trigger occurs once per combat where he's defending
• After the turn you hide a card, it gains reaction and can be played anytime you have priority

Nuances:

• Old rulings allowed Teemo to trigger when played from hidden, but this changed with the errata
• Under new rules, flipping from hidden outside combat wouldn't work anyway since there isn't a legal target
• Whether or not Teemo's trigger goes on the chain after playing him is not relevant to whether you can play him