Mortensen reports that the NFL fined Stewart $12,500 and Mawae $5,000 for late hits on Merriman, who suffered sprained knee ligaments and will miss this week's game against the Detroit Lions.
Merriman was injured in the second quarter as he was blocked downfield by Mawae and Stewart.
Earlier this week, The (Nashville) Tennessean reported Merriman claimed that Titans coach Jeff Fisher ordered that the linebacker be hurt in retaliation for the shot on Young.
"I didn't order a hit," Fisher said, according to the Tennessean. "The play was designed and you saw it on the practice field if you watched practice. We're playing ball, that's all. ... He's a good player, but we're playing ball."
The newspaper said that several Chargers told Merriman that Mawae and another player were involved in the play with intentions of hurting Merriman.
ESPN NFL reporter Chris Mortensen and The Associated Press contributed to this report.