Swearinger drew criticism all the way up to the normally reserved Broncos quarterback Peyton Manning. But O'Brien said it was clear Swearinger wasn't trying to hurt Welker.
"D.J. was not trying to do any harm," O'Brien said Sunday, according to ESPN.com. "He was trying to make a play, make a tackle. The call was correct. What you continually have to do is show the guys on tape what a proper tackle is. It's not leading with the head. It's hitting with your shoulder and hitting basically between the shoulders and the waist and not above the neck area. But last night's play was a tough one to say, 'You were really at fault there.'"
Swearinger's shoulder hit Welker's helmet late in the second quarter of the Texans' 18-17 preseason victory over the Broncos on Saturday night. For Welker, it's his third concussion in less than a year.
Manning was perhaps the most visibly upset about the hit. He immediately confronted Swearinger. And on the next play, after he threw a touchdown pass, Manning was flagged for taunting for the first time in his career when he yelled in Swearinger's direction.
It's unclear if Welker will miss any regular-season time. Per league rules, Welker will need to pass a neurological exam before he is allowed to return.
Welker suffered two concussions in four games last season. The first came in Week 11 against the Kansas City Chiefs. Three weeks later, he sustained another concussion against the Tennessee Titans. After his second concussion, he missed the final three games of the regular season, but he returned for the Broncos' playoff run that led all the way to the Super Bowl.
Welker, 33, had 73 catches for 778 yards and 10 touchdowns in 2013.