Allie Long doesn't mind shifting positions for the simple fact that it makes her a well-rounded player.

A central midfielder for most of her career with the U.S. women's national team and the Portland Thorns, Long was moved to center back for recent international matches by coach Jill Ellis.

The results have been mixed, but Long says she is dedicated to doing her part to make a new three-back system work if that's the direction the national team goes.

"If we can get it right, then it could be very, very successful," she said. "I think it just takes time."

Ellis is experimenting with players and formations as the Americans take the first steps toward defending their World Cup title in 2019. The team plays a pair of exhibitions against Russia starting on Thursday night in Frisco, Texas, then again on Sunday in Houston.

The United States is coming off a disappointing finish in the four-team SheBelieves Cup early last month.

With a 1-0 loss to England before a 3-0 loss to France, the U.S. dropped consecutive matches for the first time since the 2014 Algarve Cup. The Americans hadn't lost by such a margin on home soil since a 3-0 loss to Germany in Portland, Oregon, in a semifinal of the 2003 World Cup.

"I think the France game was unfortunate. But I also know that we needed those games. We need to kind of fail and not figure it out right away so that we could learn, and we could see and we could fix it," Long said.

She spoke at the opening of training camp for the Thorns as the team readies for National Women's Soccer League season. With the Thorns since 2013, Long has established herself as one of the league's best at her position.