NFL Network insider Jason La Canfora reported late Sunday that initial tests revealed Kaeding suffered a left anterior cruciate ligament tear, according to a source with knowledge of the situation.
Kaeding was injured on the opening kickoff, which Percy Harvin returned 103 yards for a touchdown.
"He planted, and he kind of got spread out," Turner said Monday. "There was no contact on the play."
Kaeding came into the season as the most accurate kicker in NFL history, having made 86.5 percent of his field-goal attempts -- 173 of 200 -- in his seven NFL seasons.
"Nate's unbelievable how good he's been, and we'll get someone hopefully who can be as accurate," Turner said.
Turner said the Chargers have a list of possible replacements for Kaeding. According to La Canfora, the Chargers have made initial contact with veteran kicker Nick Novak, who had a previous stint with the team, and could bring in several kickers for a competition.
As accurate as Kaeding has been during the regular season, he has made just 8 of 15 field-goal attempts (53.3 percent) in eight career playoff games. He missed three attempts in the Chargers' most recent playoff game, a 17-14 home loss to the New York Jets after the 2009 season.
The Associated Press contributed to this report.