THE U.S. MEN'S NATIONAL TEAM is in Kansas City ahead of Saturday’s friendly against Bolivia in what will be its final tune-up ahead of Copa America Centenario, which begins June 3. Wednesday night’s win over Ecuador proved revealing but it will be fascinating to see how Jurgen Klinsmann responds to the insights gleaned in that match. 

On Friday U.S. Soccer announced one significant change to the team: Edgar Castillo replaced Timothy Chandler. A limping Chandler was removed from Eintracht Frankfurt’s relegation playoff last week in the 68th minute.

U.S. Soccer indicated earlier in the week that Chandler had informed the team he was fine; apparently this was not the case. The federation also revealed that Geoff Cameron will be ready to go against Bolivia after a sore hamstring kept him out of action against Ecuador.

Here are my pregame thoughts for Saturday night’s friendly.

1. The Castillo-for-Chandler swap

This change reveals that, as suspected, Chandler was brought in as a left back despite playing only right back for his club. Now Castillo will come into replace the injured Chandler. This will have no real impact on the Bolivia game since Castillo will not be able to join the team until after Sunday's Liga MX final.

Fabian Johnson is certainly set to be the team’s left back at Copa America so the swap is more reflective of who the back-up is for that position right now in Klinsmann’s hierarchy. Castillo has been a standout in Liga MX for a long time but his international performances have never demonstrated a similar standard. Part of the reason is that he prefers to attack and his defensive game is not nearly as strong.

If the U.S. needs to push for a goal late in a game, it now has the option of moving Johnson out of left back and into his preferred role in attacking midfield. Then Klinsmann could move Castillo into the left back option.

The real concern will surface if there is an injury to Johnson and the U.S. was set to face high-quality opposition. Would Klinsmann start Castillo or would he play a more defensive-minded player at left back—like Michael Orozco? 

2. The central midfield dilemma

On just two days of rest since the Ecuador game, it would not be surprising if Klinsmann made several changes and started a lineup not considered to be his top team. That said, the game against Bolivia is the last opportunity for Klinsmann to test players and determine what combinations work best for Copa America Centenario.

Against Ecuador Wednesday night, Michael Bradley and Darlington Nagbe shined together after the latter was substituted into the game at halftime. So if those two get the opportunity to play together again, will that high level of performance continue? If it does, that bodes well for the Yanks' chances of advancing out of its group.

If Bradley and Nagbe both start, however, it will force either Jermaine Jones or Kyle Beckerman to the bench—and both were far from impressive against Ecuador. If Klinsmann elects to start Alejandro Bedoya with Bradley and Nagbe, both veterans would likely begin the match on the sidelines.

It's hard to envision Klinsmann benching Jones right now as the Colorado Rapids midfielder is on a great run of form and has been one of the coach’s favorite players in his five years at the helm. Beckerman looks like the most likely candidate to head to the bench. How Jones reacts and adjusts to Nagbe’s inclusion will be crucial. 

3. Is the 4-3-3 formation set?

Against Ecuador the U.S. began the contest in a 4-3-3 formation. It will be interesting to see if that formation is set or if the Yanks opt for a different look—or different looks—throughout the tournament. Klinsmann likes flexibility in his teams and against Puerto Rico the formation changed throughout the game.

Will Klinsmann offer something different? A 4-4-2 or a 4-1-3-2 could be useful if he feels it's best to have a two-forward setup. Such an option could be best for Clint Demspey who has typically done well with a partner up top. Dempsey is not the player he was five years ago when he could thrive in any situation. But he can still be a very useful component of the team, and that may prompt Klinsmann to create a formation that best suits his veteran forward.

4. Geoff Cameron Ready to go

John Brooks had an outstanding game against Ecuador and answered a lot of questions about his ability to handle a major tournament for the United States. In fact, in a pregame interview Klinsmann said Brooks had the most to gain from the Copa because he still felt the Hertha Berlin defender was too “passive.”

Brooks should be a starter against Colombia next week and Geoff Cameron is a very likely candidate to be his partner in central defense. On Friday, Klinsmann revealed that Cameron was healthy to start against Bolivia and this match marks the only chance to test the Brooks-Cameron pairing before the games begin to count.

How that backline responds will be key because central defense is crucial for the U.S. in a major tournament. Last summer, Ventura Alvarado (who was placed on Club America’s “transferable list” on Thursday night) fell short at the Gold Cup and the U.S. suffered. Brooks and Cameron individually have played at a high level before but it will be interesting to see how they perform as a unit.

5. Will Gyasi Zardes rebound?

In 2015, no U.S. player earned as many national team minutes as Gyasi Zardes. On Wednesday, the Los Angeles Galaxy attacker had a poor outing—both his first touch and decision-making let him down on multiple occasions before he was replaced at the half.

As a first-choice starter for the U.S. over the past 18 months, will Zardes retain his spot? Replacing him at this point would represent a major change for the club. Christian Pulisic is obviously knocking at the door to move past Zardes but so are other players, including Bobby Wood or even Chris Wondowlowski.

If Zardes gets on the field against Bolivia, he will need to convince his coach that he is still the best option despite a bad showing against Ecuador. Every minute he gets on the field will be important for him to reestablish his place on the team.

What will you be watching for in Saturday's contest? Share your take in the Comments section below.