Is Teemo Strategist considered defending when you reveal it from hidden after attackers have been declared and moved onto the battlefield?

Ruling: Yes, Teemo Strategist is considered defending when revealed from hidden after attackers have been declared. Units gain the Defender designation when they become present at the battlefield after combat has begun.

Sequence:

• You can reveal Teemo from hidden whenever you have priority during combat
• This could be before defender/attacker triggers resolve, when the attacker passes priority to you, when the attacker plays an action/reaction and passes, or when the attacker passes on an empty chain
• The unit gains the Defender designation during the Cleanup phase following the action that caused it to become present
• Defender status triggers will activate the first time the unit is flagged as a defender

Nuances:

• Attacker and defender statuses are only given once per unit per combat, but this doesn't mean they only happen at one specific time
• If a unit is added to combat after the initial designation, it still receives the appropriate status