According to Dan Pompei in the National Sunday Post, the ending of Keith Rivers' career in Cincinnati wasn't as amicable as we were led to believe (not that there was any reason to believe it). The issue boils down to Rivers' surgically repaired wrist, showing up at last year's training camp after a procedure was done that was described as a rebuilding of the wrist. Pompei writes:
There was a story behind the story on the Keith Rivers trade to the Giants. The former first round pick had surgery on his wrist near the end of the lockout last summer. The Bengals thought he could have had it earlier in the offseason, and did not approve. The team subsequently put him on the non football injury list. Rivers wanted to be put on the physically unable to perform list, which would have enabled him to collect his salary. He filed a grievance against the team. There were hard feelings, and both sides thought a fresh start was in order.
Rivers was eventually traded to the New York Giants for the No. 167 selection of the 2012 NFL draft, which later became safety George Iloka.
The obvious issue, as Pompei points out, is compensation.
According to the Collective Bargaining Agreement, any player on the final year of his contract (which also includes an option year), his contracted is tolled until he's taken off the Non-Football Injury list (where he receives all of his compensation back). However Rivers never returned and the contract remained tolled, which we largely assume to mean he didn't receive any compensation for 2011 or it was significantly reduced until the Bengals placed him on season-ending Injured Reserve in late November. Article 20, section 3 of the Collective Bargaining Agreement titled Nonfootball Injury, reads:
Section 3. Nonfootball Injury:
(a) A player who is placed on a Nonfootball Injury or Illness list (“N-F/I”) will not be entitled to any compensation under his contract while on such list but, except as provided below, his contract will continue to run while in such status.
(b) A player on N-F/I who is in the final year of his contract (including an option year) will have his contract tolled. However, if the player is physically able to perform his football services on or before the sixth regular season game, the club must pay the player his negotiated Paragraph 5 Salary (pro rata) for the balance of the season in order to toll such player’s contract. If such player is taken off N-F/I during the period when such action is allowed by League rules, his contract will not be tolled.
As we understand it, for the duration that Rivers was under the Reserve/Non-Football Injury List, he wasn't receiving compensation until he was officially placed on the Injured Reserve list. On the other hand, if the Bengals merely put Rivers on the Physically Unable to Perform list to start the 2011 season, then Rivers would have received his full paragraph five salary, but again, according to the CBA, the contract is tolled on the final year under contract.
There's no word where the grievance went after it was filed, if it's still active or if resolution was determined.