I don't think there'd be much of a difference in performance compared to the pen right now if the Cubs cobbled together a bullpen out of the guys in AA and AAA.
Throwing a meatball down the middle to someone who swings at anything close to the plate comes immediately to mind. If you're going to rip on Soto, Marmol's awesome 8th also deserves mention, as does Lee's dropped ball that got that mess going.