Though he didn't cite specific numbers, Belichick said he was citing "a matter of record not opinion," in saying injuries league-wide have been on the rise over the past three years.
League spokesman Michael Signora disputed Belichick's assertions.
"We carefully monitor player injuries," Signora said. "There is no evidence that the new work rules have had an adverse effect on the injury rate or that injuries have in fact increased."
The NFL declined to released its numbers. But according to STATS, the number of NFL players finishing a season on injured reserve has risen significantly over the past 14 seasons.
From 2000-06, there was an average of 239 players on IR. That average has jumped to about 314 over the past seven years.
The low over that span was 192 in 2001, with the high being 353 in 2010, but that was before the new offseason rules came into effect.
As of Monday, there were 288 players on IR, the lowest total since 287 in 2008.
Those figures, however, don't include players who have been on injured reserve and released by their teams during the season.
It has also been difficult to measure how many regulars have missed games due to injury.
The Patriots (11-4) have been beset by a rash of injuries to key contributors this season. They have six starters on IR, including tight end Rob Gronkowski (right knee), offensive tackle Sebastian Vollmer, linebacker Jerod Mayo, defensive lineman Vince Wilford (Achilles tendon) and safety Adrian Wilson.
Belichick insists injuries are up.
"When you see the number as high as they are, then I don't think that's a randomness that's been two years in a row," Belichick said. "I've got to think there's some correlation there."