ST. JOSEPH, Mo. -- In talking about the Kansas City Chiefs and what has been a leaky run defense, linebacker Reggie Ragland recently issued a guarantee, the kind that usually comes from the optimism of training camp.

"We're going to stop that run," Ragland said. "We're going to stop it this year. Everybody has the right mindset. ... That line, that wall, is there. We've got the guys to do it. But at the end of the day, it's all about attitude when you want to stop the run. You've got to want to do that."

Having the right attitude about such a dirty job is a nice place to start, but eventually, it's going to take more than that for the Chiefs to be successful. With that goal in mind, the Chiefs turned over much of their defense in the hope of improving from 2017, when they often had problems -- whether the opponent was running or passing. The Chiefs were in the bottom 10 last season against the run and the pass and in total yards allowed.

This season, the Chiefs are counting heavily on several defenders who either weren't with them or weren't available because of injuries last year. New to the team are cornerback Kendall Fuller, who was acquired from Washington in the Alex Smith trade, and free-agent signings in linebacker Anthony Hitchens and nose tackle Xavier Williams. Safety Eric Berry and linebacker Dee Ford return after missing much of last season with injuries.

The Chiefs also drafted defensive players with their top five picks, and some are pushing for playing time.

"That's one thing we have our mind set to," Hitchens said of defensive improvement. "We're looking forward to that challenge."

Progress has been difficult to judge for the defense as a whole because so many key defenders have missed practice time or didn't play in the preseason opener because of injuries. The Chiefs played without four defensive starters last week against the Houston Texans, including Berry, Ragland and Hitchens.

The Chiefs looked much like they did last season. They allowed a 19-yard run on the game's second play, and the starters yielded a long touchdown drive against Houston's backup quarterback, Brandon Weeden.

In practice, Fuller has looked like a No. 1 cornerback, and he broke up a pass in the game against the Texans. Williams has been disruptive at times against the run and was in on the tackle that stopped Houston running back Lamar Miller for no gain on a third-and-1 play. Hitchens has been limited at training camp because of a sore hamstring.

Three draft picks -- second-round outside linebacker Breeland Speaks, fourth-round safety Armani Watts and sixth-round cornerback Tremon Smith -- played the most against the Texans among the team's defensive players.

"It was a good test for all of them," defensive coordinator Bob Sutton said. "They all got in against the, quote, 'top guys.' What they've showed so far, I think they're in position to contribute. Over these next couple weeks in the games, we'll get a chance to see them, see how far they've come.

"They still have a long ways to go. Don't get me wrong. But I think they've shown enough that you'd say they have the aptitude [and] the talent to do this. Now, it's really whether they can drill down and get these techniques. The key is developing at this level is the consistency you have to have to be a major player from a starting standpoint or [get] major minutes out there. That to me is the biggest question going forward here."

Two third-round draft picks, lineman Derrick Nnadi and linebacker Dorian O'Daniel, didn't play against the Texans because of injuries but may get involved in Friday's preseason game against the Falcons in Atlanta.

Speaks won't be a starter because the Chiefs have veterans at his position in Ford and Justin Houston. But he will play, and the Chiefs hope Speaks can help improve a pass rush that last season was near the bottom of the league in sacks. The Chiefs have used him on occasion in the lineup, along with Houston and Ford.

Watts started at safety against Houston because of injuries to Berry and the other regular, Daniel Sorensen.

"He's a little bit hesitant on a couple things, but then he flew around on a couple things, so it was kind of an up and down ... performance," head coach Andy Reid said of how Watts played against the Texans. "There were some good things and then some things where he just needed to see it, so he can work on it. In college, he had great anticipation on plays. I think that now, that's just a matter of him being able to see a few things to do it.”

Smith at this early stage is beyond where a sixth-round draft pick from a smaller school might normally be. Smith played in college at Central Arkansas, but only because he was a late qualifier coming out of high school.

He said he otherwise would have played at Auburn, and he considers himself to be an SEC-caliber player.

"I've always knew I had that type of talent, but I just had to take a different route," he said.

Smith is the Chiefs' fourth cornerback, a position at which five of the top six players were lost from last season, including Marcus Peters.

"He was right in position to make plays," Reid said of Smith's play against the Texans. "He's another one that just needs to play. Coming from Central Arkansas, that's a different speed, but he has tremendous ability and really showed and was impressive in coverage stuff."