Quarterback Alex Smith's impact might be most felt on what he doesn't do than what he does. That's the topic of the main question in this week's Washington Redskins mailbag.

What key STAT are you looking at in judging Alex Smith play vs #8? #jkmailbag

— troy lewis (@troylew29281611) June 1, 2018

John Keim: I don’t know that there’s one stat I’ll be looking at to judge Smith. It’s easy to say wins and losses, but when Kirk Cousins was here, I’d always say you can’t judge one player that way (even at this position). There are many other factors involved.

Passing yards is another one, though if Smith doesn't throw for 4,000 yards, is that necessarily a bad season? What if it’s because the Redskins also can run the ball consistently (for a change)? With Cousins, he had to throw for a lot of yards because there wasn’t a consistent rushing attack. They were overly reliant on the quarterback; I’ll also say they remain firmly convinced Jay Gruden’s offense can help many quarterbacks throw for 4,000 yards. We’ll see.

But I’ll go to the one I know you want me to mention: turnovers. Smith has long been known for not turning the ball over. In fact, in the past five years combined, he’s thrown only 33 interceptions. In 17 fewer starts, Cousins threw 19 more picks (but only seven fewer touchdowns). We know Smith takes care of the ball, but this stat can have a tremendous impact on both sides of the ball. It’s about field position. I wrote about this in February, but here’s the stat: Last season, Washington allowed the opposition to start 23 drives inside its territory, which ranked 29th in the NFL. The Patriots allowed only five such drives (and two were kneel-downs at the end of a loss). The Redskins allowed the most drives to start inside their own 30.

That was not all on Cousins by any means. But if this stat gets turned around, the Redskins will improve. During Smith’s five seasons in Kansas City, the Chiefs allowed a combined 72 such drives. It’s no coincidence they made the postseason four times and finished with a winning record all five years. Their defense was good for his first four years, but last season the Chiefs ranked 15th in points allowed and 28th in yards. They were not great by any means. They won 10 games. Taking care of the ball (and having some offensive playmakers) mattered. One Redskins staffer earlier this offseason pointed to this stat and Smith's win-loss record in the past seven years (69-31-1) and said it was no coincidence. He pointed to his ability to take care of the ball as a main reason. He's played with some excellent defenses, too. But he helps them out by not committing turnovers.

“He definitely brings less turnovers for sure,” Redskins safety D.J. Swearinger said. “Only having five interceptions last year is something as a defender I love because I know I’m not going to be on the field the majority of the game because he’s going to manage the game. He’s a smart quarterback.”

If you had to guess, would you think Jay will keep Guice, Fat Rob, Perine, & CT...or do you think he'd prefer Guice & Fat Rob/Perine, CT, & CT insurance? I kinda feel like CT insurance would be smarter. #Jkmailbag

— Strick 9 (@Spider_Skinz) June 1, 2018

Keim: I think this will be one of the most intriguing positions to watch this summer (along with the defensive line). It’s hard to imagine them keeping only three running backs, but that fourth one had better help on special teams. The new kickoff rule means the extra backs and receivers -- the smaller, faster players -- need to help more.

Clearly, Chris Thompson and Derrius Guice will be on the roster. They’ve used Rob Kelley as their No. 1 back in the spring (for what that’s worth). But coach Jay Gruden always has liked him, and they believed Kelley was doing a solid job before his ankle injuries kept slowing him down. And do you get rid of Samaje Perine after one season? To me, he showed enough that he could be a viable backup. But I also felt the Redskins were caught when Thompson went down because nobody else on the roster could do what he did. That doesn’t mean you must carry that guy on the active roster. If they’re on the practice squad it’s OK, considering they might not be active anyway on game day.

Between Byron Marshall and Kapri Bibbs, they have possible third-down options behind Thompson. If they believe undrafted free agent Martez Carter can develop (they like him, yet thought he needed to get in better shape), then he could be placed on the practice squad and developed. That way you get four backs on the roster and a fifth who would be in your system should anything happen. Last season they didn’t even have one on the practice squad when Thompson was hurt.