It's just psychology. If this team slumps its way out of the playoffs, why would he want to stick around (even if he's partially responsible)? If he has a disappointing season (by his standards) in his one year in Chicago, why would he want to stay?
I feel like this slump is what might push Tucker out of Chicago. Not because he won't get an offer from the Cubs, but because he'll associate this terrible slump with being on this team
That right there is why Jed got his extension: after a disaster inning, everything is forgotten as we all hug and sing the stupid song and buy another beer.
I'm not sure he was broken. I think the White Sox saw him tipping pitches, plus he had unusually bad control. He's been really good before and after that disaster game