Pennington played three and the team was 1 and 2 when he got hurt. Fielder played 7 snaps. That's not a good comparison.
he also played down the stretch, and the QB depth on cleveland was ridiculous that year - their 3d stringer was Mike Pagel, who they had acquired in a trade from Indy and who was making starters money (about 250K). You don't have the luxury of that kind of depth any more.
On the other hand, they did win some games with a 38 yr old unretired free agent QB (Don Strock).