Avoid sacks and complete passes. Those, in a nutshell, are the most important parts of an NFL quarterback's job. If a passer can handle those two tasks, the rest of his assignments will take care of themselves more often than not. But Justin Fields, in his first NFL start, showed little capability of doing either.
Fields was sacked on his very first dropback against the Cleveland Browns. And his third. And his fourth. And his eighth, 11th, and 13th. That's a half-dozen sacks, nearly a 50% sack rate from the opening kickoff into the third quarter. And things weren't that much better even when Fields was able to get a pass off—he only completed three of his first seven passes for a total of 29 yards, with none of those completions picking up first downs.