Every single player that will represent the U.S. at the Women's World Cup this summer plies her trade in the National Women's Soccer League, and when coach Jill Ellis announced her roster Thursday for the tournament, she espoused the importance of the NWSL.

"The NWSL as a platform and environment is absolutely necessary for us to be able to compete for world championships," Ellis told reporters. "Every top team in the world has a league that's thriving, so I think that's critical.

"I can't say enough in terms of the importance of having a strong domestic league."

And yet, despite that, the World Cup roster as constructed seems to give little credence to what happens in the NWSL in comparison to each player's international history. Many U.S. players are being asked to play different roles than they train for daily with their clubs. Other roster decisions seem to have nothing to do with club form.

It raises the question: how much does the NWSL really matter in national team decisions, and should it matter more?

One of the biggest roster snubs offers clear-cut reasons to wonder. Missing out on the 23-woman roster is Chicago Red Stars fullback Casey Short, who two weekends ago did an expert job closing down one of the world's best wingers and fellow American Tobin Heath. Short has been one of the most consistent fullbacks in the NWSL, but she failed to earn a World Cup spot.

What is more surprising, however — at least purely from an NWSL standpoint — is who earned spots over Short.

View photos Crystal Dunn is a forward for the North Carolina Courage, but will be switching to defense for the USWNT. (Getty Images) More

Crystal Dunn will be starting at left back, Short's usual spot for the U.S., despite the fact that Dunn doesn't play as a defender at all in the NWSL. Dunn is an attacking player for the North Carolina Courage, so much so that she currently leads the NWSL Golden Boot race with four goals and one assist in three games so far this season.

At the U.S. right back spot, it's the same thing. Emily Sonnett, who has been the No. 2 U.S. right back and has started while Kelley O'Hara has been injured, plays as a center back for the Portland Thorns, not as a right back. O'Hara, the presumed starter, has moved around the field in NWSL play over the years, switching from the back line to the attack.

But it's not as if O'Hara has played much this season anyway. She's coming off injury, and even though she's been playing limited minutes for her club, Ellis believes the national team can get the most out of her.

"We now have four or five weeks, so my anticipation is that Kelley will be back, productive and willing to help us whether it's starting or off the bench," Ellis said. "Once a player has shown me they're playing, I still think we have enough time to build the fitness in the next few weeks."

That raises the question of club form and how much it mattered in Ellis' decisions.

Central midfielder Morgan Brian has struggled with the Chicago Red Stars over the past two years, both due to injury and apparent confidence issues. When Brian went on loan to Olympique Lyon last year, she could barely crack into the lineup even when healthy and her loan ended early. Those issues with her form have spilled into the national team and Brian struggled at March's SheBelieves Cup, which apparently prompted Ellis not to call Brian in for April's friendlies vs. Australia and Belgium.

And yet Brian will be headed to France. It's not based on club form, which has been poor. Rather, it seems to be based primarily on her past experience with the U.S., particularly at the 2015 Women's World Cup.

"As much as you want to focus on here and now, you also know what someone is like," Ellis said. "Some players you don’t know until they're in that moment of the pressure cooker of a World Cup quarterfinal. Having been on that journey with Moe helped her and helped me in my decision."

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