Who freaking cares, this is a non-issue and only brought up if you're looking for something to rage about. If Frost has a successful season he is back in 2023. If he has another season like this one, he is gone. If it is somewhere in between that is for Trev to decide and his decision will anger/ frustrate just as many as it pleases.
Any metrics to be met are probably in a performance improvement plan locked away in a HR file somewhere and have no place in a publicly released document anyway.