The Washington Post reported on Sunday that according to sources, Haynesworth likely will be interviewed some time this week by league officials.
The Redskins refused to comment on the matter to the Post.
The Titans, who registered charges with the league in late March, were trying to re-sign Haynesworth after the 2008 season, but believe they were interfered with by the Redskins.
The Titans are accusing the Redskins of contacting Haynesworth and his agent, Chad Speck, before the free agency period started Feb. 27. Yahoo! Sports reported that according to two sources, the league already has talked with at least two people who are linked to the case.
The Redskins could lose a draft pick if the league proves that they committed tampering.
Haynesworth signed a seven-year, $100 million contract with the Redskins -- a deal that was agreed upon early on the first day of free agency. The contract includes $41 million in guarantees.
Both Speck and NFL spokesman Greg Aiello declined to comment to Yahoo! Sports.
In a March interview with The (Nashville) Tennessean, Haynesworth said he did not believe the Redskins were guilty of tampering. "All I know is the Redskins called my agent at 11:04 p.m. Nashville time [12:04 a.m. ET on Feb. 27] and they started negotiating then,'' he said, according to The Tennessean. "They weren't anywhere close in the first couple of hours and then they got serious. Chad worked the deal then and it worked out.''