Defenseman Brent Seabrook was placed on regular injured reserve.
Dach is expected to miss four-to-five months after he underwent surgery to repair a wrist fracture suffered at the world juniors. Toews revealed in late December that he would be out indefinitely due to an illness that has left him "feeling drained and lethargic." There is no current timeline for his return.
While Dach is likely out for the entire season, Toews' placement on LTIR means he'll miss a minimum of 10 games and 24 days, according to The Athletic's Mark Lazerus.
Toews posted 60 points in 70 games last season in a key role for Chicago. With the captain and Dach both out, the Blackhawks' depth at center is limited.