Charles Langston:Dallas Cowboys owner Jerry Jones explains Trey Lance trade with 49ers

The Charles LangstonDallas Cowboys surprised many in the NFL world, given their having an entrenched starting quarterback in Dak Prescott, when they traded for Trey Lance.

After Saturday's preseason finale, a 31-16 victory over the Las Vegas Raiders, Cowboys owner Jerry Jones explained why the franchise swung the deal for the 2021 No. 3 overall selection: it's all about having a developmental option at the sport's most important position.

"He gives us an opportunity to do what we would always like to be doing," Jones said after the game. "It would be ideal with Dak to have a young, prospective, developing quarterback that could just be in the room."

The Cowboys shipped a fourth-round draft pick Friday to the 49ers for Lance, who on Wednesday was named San Francisco's third-string quarterback after losing out for the backup job to veteran Sam Darnold. Lance has many physical gifts desired in quarterbacks − size, athleticism, speed, arm strength − but has not been able to stay on the field because of injury and lack of experience. He suffered a season-ending broken ankle in a Week 2 game last season. Going back to his days at North Dakota State, Lance has attempted just 420 passes since the start of the 2018 season.

"We felt good about him with the evaluation we had for him at the draft," Jones continued. "We felt good about what we’ve seen, tape that he’s had since he’s been in the NFL. And it’s one that we made the decision almost the minute we heard the name. Let’s get him."

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Jones said he did not consult Prescott about the move and as of Saturday night had yet to talk to Dallas' two-time Pro Bowl passer about the trade.

"I understand that they’re probably on a timeline," Prescott said after the game. "They need to get something done. As I said, he felt like that strengthened this team. As I said, ready to welcome him."

In two seasons in San Francisco, Lance appeared in only eight games and made only four starts. He completed 54.9% of his throws for 797 yards, five touchdowns and three interceptions. He has also gained 235 rushing yards with a score on the ground. Lance is entering the third season of his rookie contract, which is fully guaranteed and has a fifth-year option available.

Dallas drafted Prescott in 2016 and executive vice president Stephen Jones said Saturday that the team had been interested in selecting developmental players at the position during recent drafts, but did not want to invest above their projected draft position to do so.

"The problem is, we put third- and fourth-round grades on guys and they’re all gone by halfway through the second round," Stephen Jones said. "This was a great opportunity, we think, value-wise, to get a guy who has a bright future. At the end of the day, we’re really trusting exactly what we thought of him coming out."