Not sure if you are getting the rule mixed up.I must admit i thought the same as you originally,but then had doubts.
16.3.2 A rider in a Team's declared 1 - 7 at the end of the previous season and not included in that Team’s new season’s initial declaration may not be subsequently re-introduced into that Team without the express permission of the Directors.
With Proctor being on such a low average that is the appeal in wanting him i would imagine.