Contracts have not yet been signed, although verbal agreements are in place. The UFC Fight Night event will take place inside Copenhagen's Royal Arena and will air on ESPN+.
Cannonier (12-4) is on a roll since dropping to 185 pounds late last year. He knocked out David Branch in his UFC middleweight debut in November, and he followed that with a first-round TKO of Anderson Silva at UFC 237 in May. The 35-year-old went 3-4 in seven appearances in the UFC's light heavyweight division.
Hermansson (20-4) also is on the best run of his career. The Norwegian will go into the Sept. 28 matchup riding a four-fight win streak, which includes victories over Branch and Ronaldo "Jacare" Souza.