The Dallas Cowboys have lurched back and forth between two extremes.

The Cowboys (2-3) have been anemic on offense and prone to giving up big plays on defense in three road losses, starting with the season opener at Carolina and in Weeks 3 and 5 against Seattle and Houston.

They have been more efficient with the ball and stingier on defense in wins against the New York Giants and the Detroit Lions at home, where they will be Sunday when they play host to the Jacksonville Jaguars.

The Jaguars (3-2) are minus-7 in turnover ratio and have committed 11 more penalties than their opponents through five games but still have a winning record.

Jacksonville has lost five fumbles and Blake Bortles has thrown seven interceptions. Compare the 12 giveaways to the Jaguars picking off three passes and recovering both of their opponents' two fumbles for a total of five takeaways.

The negative-7 leaves the Jaguars near the bottom of the NFL in turnover ratio, and it's a statistic that concerns Jacksonville head coach Doug Marrone as one that the Cowboys will try to exploit.

"We're 3-2 but minus-7, which is really tough to do, be 3-2 and be minus-7 in the turnover ratio," he said. "It's a trend that I talked about with the team today. If we don't change that, we're going to be in trouble. We have to change that."

Bortles Blake faces a Cowboys defense that has fared better against pocket passers so far this season. Their losses have come against teams with dual-threat quarterbacks.

But Bortles might throw a bit of a wrench into the predictability of that pattern. While he doesn't have as many rushing attempts as Houston's Deshaun Watson or Carolina's Cam Newton, Bortles has run more than twice as much as Seattle's Russell Wilson and has outgained Newton in rushing yards 166-165 this season.

"Like you try to disrupt the rhythm of every quarterback, I think it starts up front," Dallas head coach Jason Garrett said. "You have to somehow, some way try to affect him with your pass rush. Rush and cover work together."

Cowboys defensive end DeMarcus Lawrence is more of a menace for less mobile quarterbacks, such as the Lions' Matthew Stafford, who was sacked three times by Lawrence.

"Really important for us to guard the guys in the back end, not give (Bortles) easy places to throw the football," Garrett said.

The Cowboys' ability to slow down the Jaguars' offense might hinge on the team's running back situation. Jacksonville had more than 500 total yards last week but lost to the Kansas City Chiefs.

With Leonard Fournette battling a hamstring injury and third-stringer Corey Grant (foot) on injured reserve, the Jaguars signed free agent Jamaal Charles on Tuesday.

Fournette will miss his fourth full game this season, left tackle Josh Wells (groin) will be out after starting the last three games for injured Cam Robinson, and nickel back D.J. Hayden (toe) hasn't played since his injury against New England in the second game of the season.

Charles will serve as the main backup to T.J. Yeldon, currently the team's only healthy running back.

A 10-year NFL veteran, Charles was a reserve behind C.J. Anderson and Devontae Booker with the Denver Broncos last year. He rushed 69 times for 296 yards (4.3 yards per attempt) and one touchdown in 14 games. Charles still holds the NFL career record average of 5.39 yards per attempt for players with at least 1,000 carries.

Knee injuries have limited Charles the past three seasons.

"I feel good. Last year, I was trying to get back to feeling good and get back healthy again," Charles told local media on Wednesday. "Now, I have been out for a while, but I have also had time to get my body right and get stronger and get healthy. I feel great.

"I feel like (the Jaguars) have a contending team and I was happy when they called. I want to win a Super Bowl. That is why I kept my options open, because I did want to win. I want to win a Super Bowl and they have a good chance to do that, so I came here to contribute."

For the Cowboys to be contenders, quarterback Dak Prescott likely will have to step up his game. He has completed 89 of 144 passes this season (61.8 percent), good for 28th in the league, with five touchdowns and four interceptions while working with a new group of wide receivers.

"When he's in a really good position, he can be a very accurate passer," Garrett said. "I think we've seen that throughout his career up to this point and I think that's something you have to continue to work with him on."