Fisher, a center, strained a ligament in his right knee during a shootout loss to the New York Rangers on Monday night, the Senators' fifth straight loss, which dropped them to last place in the Eastern Conference. The injury will not require surgery.
Neil, a right wing, tore the meniscus in his right knee on Saturday in a loss to the New York Islanders and will undergo surgery. He's expected to miss at least a few weeks.
Fisher has two goals and four assists in 16 games, and Neil has two goals and an assist in 17 games this season.