The Oakland Raiders' rise to become one of the NFL's better teams has happened at an exceedingly cost-effective rate. The Raiders are the only team yet to reach the spending threshold mandated in the collective bargaining agreement, according to league sources. The club has a few months to spend the required money itself. Otherwise, the NFLPA will do it for them.

Under the new CBA, all NFL teams are mandated to spend at least 89 percent to the salary cap in cash in a four-year period by the time the 2016 league year concludes. Currently, the Raiders remain below that mark, the sources said, and if they do not reach that level of spending the union would receive the difference in cash and get to assign the funds as it sees to fit, per the CBA. The NFLPA could distribute it to needy current and former Raiders who played for the team during that four-year span, for instance.

Of course, it's more likely the Raiders use this gap as further incentive to re-invest in their young team. Quarterback Derek Carr could begin negotiations this offseason, but that deal would be complicated and likely far off, sources said. Starting running back Latavius Murray is a pending free agent who the team has interest in retaining.

A player who received a signing bonus between now and the start of the 2017 league year (March 9) could have a portion of that bonus applied to the 2016 cap for purposes of a team complying with the spending rule.

Oakland is not significantly under the mark, the sources said, but it would obviously be preferable to reach it rather than be the first team to go through this new process with the NFLPA. The Panthers are the next closest team on the low spending chart, sources said, and are barely over the 89 percent target.