Hubbard is only 4.9 this year and even if cut is still a 1.3 hit in 2021.
No all-pros are sitting around waiting for a 3.6 salary.
Sure, don't resign the guy for 2022 [presuming other OL are trained into serviceability via Callahan] - but sometimes sitting on hands is the best move a GM could do.
Last year's playoff run showcased the importance of competent depth, and Hubbard was a part of ours then.. KC showed what happens when you get caught gambling with the cap by not investing in bench OL.
And if Hubbard gets signed by someone else for 2022.. take the comp pick.
Only very rarely can you have an actual starter on your bench.. have realistic expectations of those being our backup OL.. mostly it's either reclamation projects / athletic but inexperienced projections [aka Brock Lesnar to the Vikings] / or barely-capable 7th round pluggers who appear useful one game each year because the other guy has an undisclosed injury.