In one aspect, a method includes identifying an upcoming content-modification opportunity on a channel, where the upcoming content-modification opportunity relates to a modifiable content-segment transmitted by a content-distribution system on the channel, and where the modifiable content-segment includes an overlay content portion and a non-overlay content portion. The method also includes responsive to identifying the upcoming content-modification opportunity on the channel, identifying a content-presentation device tuned to the channel. The method also includes determining location data associated with the overlay content portion. The method also includes transmitting, to the identified content-presentation device, the determined location data to facilitate the content-presentation device performing a content-modification operation in connection with the identified upcoming content-modification opportunity on the channel, where performing the content-modification operation involves replacing only the non-overlay content portion with supplemental content.