Jill Ellis' lineup and tactical tinkering may have cost players performance bonuses, but it's been in service of the bigger picture. (Associated Press)

LOS ANGELES – You can call it experimenting, or tinkering, or testing. But United States women's national team forward Christen Press prefers a broader term: preparing.

"We have been preparing for the World Cup since the moment that we finished the Olympics in 2016," Press told Yahoo Sports. "We have been trying new things out, which just basically means preparing – it's trying different shapes, different personnel, all of that."

Potato, potahto – whatever it's called, coach Jill Ellis has been doing a lot of it with the USWNT, and it's made for some surprising and, at times, head-scratching lineups. Ellis has shoehorned players in new positions, tried new formations and thrown rookies off the deep end to sink or swim. Just when it seems like Ellis has moved on from experimenting, she finds a new and equally unpredictable wrinkle to try.

Against Belgium at Banc of California Stadium on Sunday, Ellis shocked even the most attuned USWNT followers by starting defender Ali Krieger, who hadn't played with the national team in almost two years to the day. On top of that, Ellis asked the team's only true defensive midfielder, Julie Ertz, to reprise a role as a center back, while usual fullback Crystal Dunn went up into the central midfield.

Dunn admits switching on and off from being a defender isn't always easy. It can take a beat or two to switch her brain back to fullback mode. But that challenge, brought on by constant tinkering, makes her better prepared for how crazy a World Cup can potentially get.

"I know if there is an injury or there is a rotation, I need to be at my best and be able to connect to whoever I'm playing with in that moment," Dunn said. "I always try to make it my business in training to feel connected with the other 23-plus players and be ready if I might need to play with someone new."

In other words, it's okay to feel uncomfortable during experiments because the World Cup will feel uncomfortable.

"Everything has a purpose," Ellis said. "It's about looking at all the pieces and how they fit together."

The problem, however, is that sometimes when the pieces don’t fit together, Ellis and the coaching staff still try anyway, determined to get the results they want from an experiment.

Mallory Pugh, for instance, featured in last month's SheBelieves Cup in the central midfield – a position she has never played – against the top teams in the world. Predictably, it didn't go very well from the start.

While Pugh is pacey and aggressive in scoring goals along the flanks, she's not a ball-winner and isn't used to needing to control possession, which are essential in the central midfield. But Ellis continued to play Pugh there throughout the tournament, seemingly in hopes of an improvement.

Megan Rapinoe admits that throwing Pugh into a new position during a tournament of top teams probably wasn't going to be a success. But it provided answers about how the USWNT can change its look when it needs to adapt.

“Obviously, I don’t think I’ve ever seen Mal Pugh play in the No. 10 or the 8, whatever the position is, depending on the side,” Rapinoe said. “I didn’t expect her to have spectacular performances at the highest level in a position she’s never played in. Part of that is we need to be versatile and we need to put ourselves in uncomfortable positions, and at times you have to sacrifice results to see different things.”

View photos USWNT players are OK with the trade-off of performance bonuses vs. what's best to help them win the World Cup. For now. (Getty) More

There's also the fact that Rapinoe has been playing so well along the left flank, along with Tobin Heath on the right flank. There's no room for Pugh on the wing, and Ellis was curious if there was another way to get Pugh on the field.

“We’ve got world-class players sitting on the bench,” Ellis said. “So you look and you say: Is there a possibility here? You owe it yourself if you can get talented players on the pitch.”

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