The hitting, defense, and starting pitching all suck. The bullpen is the only bright spot.
As Bud said, an Ace closer is the keystone – everyone else falls into their roles.
Trade Bell, and you’ve lost the Gregerson-Adams-Bell rotation that sets up the bullpen.
That’s a big risk when everything else is going to Hades in a basket. 100 losses
won’t attract the casual fan, and the franchise needs the attendance revenue.

OTOH, if the extension talks go nowhere, the Padres will have to trade Bell.
They can’t afford him without some kind of discount, and if he stays all year,
they’d have to offer arbitration to get compensatory picks for him signing elsewhere,
and he’d probably accept arbitration to stay one more year.