The Giants reverted Koo to their practice squad Monday, per the NFL's transaction log.
Koo was elevated for Sunday's Week 10 loss to Chicago and made both of his field-goal attempts and both of his extra-point tries. His elevation was a result of veteran kicker Graham Gano missing the game due to a neck injury. Koo will likely be the Giants' kicker again Sunday versus Green Bay if Gano isn't ready to return to action.