If the Bears insist on doing this, they might as well make the most of it.

They’ll start quarterback Justin Fields against the Bills on Saturday, and as much as he needs the work, playing him behind a patchwork offensive line in a preseason game is too big of a risk for too little of a reward.

But the decision is made, so the Bears will use this as another step toward getting Fields ready for the Sept. 10 opener against the Packers. And they’ll be looking for signs of progress.

Fields has had good moments in training camp, but has yet to show the steadiness that would solidify him as the franchise quarterback. This is by far the best roster the Bears have put around him in his three seasons and that will inherently lead to some improvement, but Fields hasn’t made a convincing case that he has improved individually.

Improved as a passer, that is. There’s never been any doubt about his running ability.

But Fields and the Bears learned the hard way that’s not nearly enough. He became the third quarterback in NFL history to reach 1,000 yards, but finished last among starting quarterbacks at 149.5 yards passing per game.

That’s a jarringly low output. Mitch Trubisky averaged more than 200 yards over his Bears tenure, as did Nick Foles. Even Andy Dalton topped 180. The last Bears starter to average fewer yards passing was Kyle Orton as a rookie in 2005.

As Fields tries to develop, the key is precision in every aspect, and facing a strong Bills defense is a good test of how much better he has gotten.

His throwing has to get sharper after a season in which Pro Football Reference ranked Fields 28th in accuracy at 71.1%. His 60.4 completion percentage — barely up from his rookie season — was 31st among the 33 quarterbacks who threw at least 200 passes.

Part of the problem was the Bears didn’t have receivers who could get open, but DJ Moore is an instant solution because he always is. Moore can change everything for Fields, whether on a screen pass or a deep shot, but Fields has to be accurate enough to maximize that new weapon.

Moore leads the revamped wide receiver room, but Chase Claypool and Darnell Mooney will factor significantly and both still need to establish cohesion with Fields. Mooney had a choppy season before an ankle injury knocked him out, and it would be good to see Fields connect with him Saturday. As for Claypool, he has missed more than two weeks. That’s problematic, but there’s nothing Fields can do about it.

When Fields played seven snaps against the Titans in the preseason opener, he didn’t attempt a pass beyond the line of scrimmage and didn’t hit Mooney. It’d be encouraging for the Bears if he does both against the Bills.

That intermediate passing game is crucial for Fields. He has shown a great deep ball and has help from Moore and others to turn short passes into big gains, but those won’t always be there. He has to be reliable in the middle range, and part of that is learning to take advantage of a defense’s preoccupation with his running ability.

While everyone wants Fields to prove he can hang in the pocket, he doesn’t necessarily have to do it that way. He can scramble away from pressure to buy time to throw rather than sprint for as many yards as he can get.

The key is maintaining a wide view downfield while on the move. Now that he has multiple receivers — plus tight end Cole Kmet and running back Khalil Herbert — who can get open regularly, it’s imperative he doesn’t miss those moments because of narrow vision.

Fields might ultimately be just fine regardless of training camp hiccups, but it’d certainly be reassuring if he gave some concrete proof Saturday.