Days after dropping out of the race to become the NFL Players Association's new president, Russell Okung has vowed to pursue discipline for the NFLPA's own executive director, alleging that DeMaurice Smith helped silence and threaten players during the NFLPA's recent negotiations over a new collective bargaining agreement with the NFL.

As previously reported, Okung on Monday filed a formal complaint to the National Labor Relations Board, a federal agency governing labor practices, accusing Smith, the NFLPA's executive director since 2009, of negotiating the CBA in bad faith. On Thursday, Okung detailed his accusation by posting to Twitter a letter from additional, external legal counsel he's using to "pursue this claim."

"The NFLPA staff leadership cut members of the Executive Committee out of the process, in violation of its duties to membership," the letter reads. "Asked to consider the proposed CBA, the Executive Committee recognized the proposal's failings and the need for amplification of certain provisions, and voted not to send the proposal to the rank and file. The NFLPA staff leadership, in violation of its duties, ignored the Executive Committee, and sent the proposal to the membership for a vote."

Okung, of course, is referring to the Executive Committee of which he's a part -- the same one that voted in February, 6-5, to recommend not passing the NFL owners' proposed CBA to players for a majority vote.

Additionally, Okung's NLRB complaint argues that the NFLPA tried to silence him "with threats of criminal prosecution and union sanction," as ProFootballTalk reported.

All registered NFLPA members (i.e. NFL players) have until Saturday at 11:59 p.m. ET to cast a "yes" or "no" vote for the proposed CBA, which would expand the NFL postseason and later the NFL regular season, among other things.