The club have confirmed 32-year-old Dawson sustained a significant medial collateral ligament injury in Tuesday's pre-season win at Mansfield and will spend the next six weeks in a leg brace.
Hull are already without goalkeeper Allan McGregor, centre-back Alex Bruce and full-back Hull full-back Moses Odubajo for the first half of the club's return to the Premier League.
McGregor had an operation on his back on Tuesday, Bruce had surgery last week to remove a bony prominence in his foot while Odubajo has ruptured knee ligaments.
In the shorter term midfielder Tom Huddlestone's ongoing Achilles problem means he will miss valuable pre-season time as he faces a fortnight on the sidelines, as will Jake Livermore because of an ankle injury picked up in training this week.
However, striker Adama Diomande returns to training this week and should be in contention to feature against Scunthorpe at the weekend.
Source : PA
Source: PA