Quote from Disco Dogs, answering my similar questionL
"He will go to the first team he appears with as long as he has a qualifying season with that team, meaning 50 pa’s or 25 IPs with that team, other wise he will go to the second team, for example Mitch Webster comes up with a team, has 1 PA then goes to Montreal for 180 PAs or so, so even though it shows a combined season for both team, he has no qualifying season for the first team, so he goes to Montreal."