He didn't want to be here.
And to be honest, while I instantly saw the difference between the two in how they read progressions. He is still very inconsistent and has one good game followed with 2 average to bad games. He played good against Green Bay, but then tanked the following weak against Oakland when the Chiefs had a chance to make the play offs and threw two interceptions and struggled to help the offense move the ball.
Picking between Cassle and Orton is basically picking your poison. They both will probably give you the same type of production through out the year.