Adding Holzer was Nashville's only addition on Wednesday. The team currently sits two points out of a wild-card spot in the Western Conference.
The 32-year-old Holzer has suited up for 46 games in 2019-20, scoring four points, blocking 85 shots, and averaging over 16 minutes of ice time per game.
Irwin, meanwhile, amassed two assists in 27 contests for Nashville this season. He had been in and out of the lineup because of the Predators' deep blue line.