Unique League QB Start?

I have a unique League with a QB question.

The league is a college themed, multi-copy league. The only available players are 4 years experience or less, with an option to Taxi Squad a 1st year player, to give them an extra uear of availability, but must stay kn the taxi squad all year.

I currently have Mayfield as my Qb, but has been hurt and a disappointment. I have Fields on my taxi squad. I need to win the rest of my games for a chance at the league playoffs.

If I pull Fields from my Taxi, then I only get him for the remainder of this year, plus 3 years. I am strongly considering pulling up Fields.