Hi, I recently caught a Stantler in my HeartGold game with Frisk, mainly for the purpose of helping me find wild Pokemon that are holding items (e.g. Abra with a TwistedSpoon, Ditto with Metal Powder), just wondering, but if my Stantler is at the top of the party when sent into a wild Pokemon battle, can it tell when a wild Pokemon is holding an item?

Or do I have to make a switch for Frisk to work?

Either way, thanks in advance.