Rare is it that rookies hold out from minicamp anymore.

Under the collective bargaining agreement in 2011, the rookie wage scale doesn’t allow for much negotiations, which means that rookies are often at voluntary minicamp with their contracts finalized.

Joey Bosa, however, is the exception to the rule.

The former Ohio State star is the last of the first 19 picks in the 2016 NFL draft to be unsigned. As a result, Bosa skipped last Thursday’s final OTA practice as well as Tuesday’s minicamp.

So why hasn’t Bosa signed yet? Well, it’s not as simple as most holdouts.

Under the rookie wage scale, Bosa is projected to make just south of $26 million with a $17 million signing bonus. It would best Ezekiel Elliott for the largest contract signed by a B1G rookie since the scale was put in place in 2011. But those figures aren’t the cause of the stalemate.

According to the San Diego Union-Tribune, the offset language in the contract is the hurdle separating an agreement. The Chargers put a clause in place of all of their big contracts (Philip Rivers and Melvin Gordon had it, too) that states that if the team releases them, they only owe the difference between their old salary and their new salary.

RELATED: Bosa talks J.J. Watt comparisons, nicknames and Meyer vs. Saban

Bosa’s representation is pushing for that to be dropped. In other words, that would mean that if the Chargers cut Bosa, he could sign with another team and receive that contract, in addition to the full contract he signed with San Diego.

Essentially, it’s double-dipping.

According to the Union-Tribune, Marcus Mariota held out of camp for the same reason. Of the top-five picks in the draft from 2015 and 2016, six of the nine have offset language in their contracts, including former No. 1 pick Jameis Winston.

It remains to be seen which group Bosa will fall into.

The two-time All-American was expected to provide an immediate impact after the Chargers selected him at No. 3 overall. If the holdout continues deep into the summer, it could prevent Bosa from doing that.