@EA - Why can't we use evolved strahan to evolve others?

As the title states. Any answer would be appreciated.

thanks.

Quote from doctorjsh >> is he in your lineup? you have to put him on your bench to exchange him

 I did pull him out of line up but no go

Quote from ickyswood >> i used strahan to evolve shazier

 Was yours an evolved Strahan?

is he in your lineup? you have to put him on your bench to exchange him

i used strahan to evolve shazier