Defender Bonucci is out with a muscular problem having revealed he had played on with an adductor injury during the second half of Juventus's 1-1 draw with Lazio prior to the international break.
The centre-back had not featured in Friday's (AEDT) friendly against Estonia, a game the Azzurri won 4-0 to stretch their unbeaten run to 20 matches.
"I wanted to be there at all costs, but unfortunately I can't," Bonucci said.
"I pushed hard and gritted my teeth in the last 20 days, including against Lazio in the last half-hour when I felt discomfort.
"Unfortunately it is a crescendo of pain, I am forced to stop. In Turin, we will evaluate the recovery times."
Gagliardini, meanwhile, has left the national squad ahead of the fixture against Poland in Reggio Emilia after returning an inconclusive result in Saturday's (AEDT) COVID-19 tests.
The Inter Milan midfielder tested positive at the start of October, but had seemingly recovered as he was cleared to return to action for his club.
After coming off the bench in Inter's 1-1 draw with Atalanta on 9 November (AEDT), the 26-year-old played the entire game for Italy against Estonia.
However, with the outcome of a second swab test taken on Sunday (AEDT) still not known, the Italian Football Federation announced Gagliardini is to return to Milan, meaning he will not be part of the travelling party for the trip to Sarajevo either.