A source told NFL Network that Kroft has a three-to-four-month timetable for recovery, which would be a tight turnaround for Week 1 of the regular season.
Kroft was to have foot surgery Tuesday.
"Tyler Kroft sustained a broken foot," McDermott told reporters. "He'll have to surgery today. Cole Beasley and Mitch Morse both underwent surgery a few weeks ago and are working back to getting healthy. They both underwent core muscle procedures."
Kroft, 26, had 36 yards on four receptions in five games last season for the Cincinnati Bengals. The 6-foot-6, 252-pound pass-catcher signed a three-year, $18.75 million pact with the Bills in March in free agency.
Kroft had a career-high 404 yards and seven scores on 42 receptions in 16 starts during his 2017 campaign in Cincinnati. He entered the league as a third round pick by the Bengals in the 2015 NFL Draft.
The Bills also have tight ends Jason Croom, Dawson Knox, Lee Smith, Moral Stephens and Tommy Sweeney on the rostered during OTAs.