The expression "saddle with" refers to the act of burdening or imposing something undesirable on someone or something. Antonyms for "saddle with" would be words or phrases that refer to the act of removing or relieving a burden. Some possible antonyms could be "unburden," "disencumber," "remove," "free," "discharge," "liberate," or "release." For example, you could use an antonym of "saddle with" when describing a situation where someone has been relieved of a heavy workload or financial burden. Instead of saying they were "saddled with" those responsibilities, you could say they were "unburdened" or "freed" from them.