The NFL Players Association is investigating the relationship between agent Drew Rosenhaus and former financial adviser Jeff Rubin, Yahoo! Sports reported.

One main issue is whether Rosenhaus knew or should have known that Rubin advised a number of Rosenhaus' clients to invest in an Alabama bingo casino that went bankrupt.

Players lost up to $43.6 million in Rubin's casino downfall, according to the report, and multiple sources, including Terrell Owens, told Yahoo! Sports that Rosenhaus actively recruited players with Rubin. That goes against NFLPA policy.

Rosenhaus denies any impropriety on his part

"Let me say this on the record, I had no reason to believe that Jeff Rubin was doing anything illegal or irresponsible or unethical," Rosenhaus told Yankoo! Sports. "We never had any inkling that he was ever dishonest. We never had a player come to us until this casino fell apart."

Owens claims Rosenhaus tried to direct him to Rubin.

"We recommend you use Jeff," Owens said Rosenhaus told him, according to the report. "He handles our clients, we trust him."

Owens thinks Rosenhaus bears at least some of the responsibility.

"With what I know now, Drew definitely needs to share in the responsibility. ... Other players may not want to speak up out of loyalty to Drew but at the end of the day he bears some of the responsibility (for our losses) based on the referrals he was giving to [Rubin] and Pro Sports Financial," Owens said.

This players' union probe seeks to determine whether Rosenhaus' business relationship with Rubin was improperly close and whether Rosenhaus should have paid closer attention to his dealings with his clients and kept them away from Rubin.

If it's determined that Rosenhaus violated NFLPA regulations on agent conduct, he could be disciplined by the union.