As of right now, the Dallas Cowboys have an astounding $61MM of 2019 cap space tied up in their offensive line. Four of their top seven cap values belong to offensive lineman:
All four of those players are offensive lineman that they drafted (Collins was signed as an UDCFA but he was essentially drafted by Dallas - long story) and all were re-signed after their rookie deals. The last time the Denver Broncos re-signed an offensive lineman that they had drafted when their rookie deal expired was Ryan Clady.