The phrase "be in the same league" implies that two or more entities are of similar caliber or quality. The antonyms for this phrase are phrases like "lag behind," "be out of one's league," and "be mismatched." These phrases describe situations where there is a significant imbalance in skill or status. For example, a high school basketball team would be out of their league if they played against a professional NBA team. Similarly, a novice chef would be mismatched if they competed against a Michelin-starred chef. In these situations, the outcome is predictable, and the entities involved are not in the same league.