The Detroit Lions are disputing the exact terms they'd have to meet if they want to keep defensive end George Johnson, whom the Bucs tendered a three-year, $9 million contract to. The Lions have the right to match that contract and keep Johnson, but they are asking for an arbitrator to clarify what exactly they need to match.
The natural speculation was that the Bucs included some form of poison pill, whereby Johnson would cost the Lions more than he'd cost the Bucs under the same contract, but Pro Football Talk reports that the dispute is over de-escalators and the Lions want to know whether they need to meet the $9 million contract with de-escalators, or a de-escalated $7 million contract. The collective bargaining agreement could be read two ways on this issue, so an arbitrator gets to decide.
Intriguingly, this is really a case of clarification. Those de-escalators have no impact on the immediate cap hit the Lions would have to absorb, as any de-escalators are almost certain to apply to future years -- and any that apply to 2015 would only go into effect at the end of the season, meaning Detroit would still have to clear the same cap room until those de-escalators hit.
Regardless, the fact that the Lions are even asking for clarification means they likely want to keep him -- and Johnson's reported $2.75 million cap hit in 2015 isn't prohibitive for Detroit. So I'd expect the Bucs to fail to add a defensive end for at least the fourth time this year.