Edgar Castillo in for Timmy Chandler on U.S. Copa America squad

Monterrey defender Edgar Castillo will replace the injured Timmy Chandler in the United States' Copa America squad, pending approval from the organising committee.

Manager Jurgen Klinsmann said on Friday that defender Geoff Cameron has recovered sufficiently from a hamstring injury to be able to play in Saturday's friendly against Bolivia, the last tune-up before the start of Copa America on June 3.

Chandler will miss the tournament due to a right quad strain. The U.S. has applied to make a roster change, and if approved, will see Chandler replaced by Castillo. Castillo won't join the team until after the second leg of Sunday's Liga MX final against Pachuca.

Chandler, who helped Eintracht Frankfurt win their relegation playoff against Nuremberg on Monday, arrived at the U.S. camp with a right quadriceps strain.

The 26-year-old limped out of Monday's Bundesliga match, but earlier this week a U.S. team spokesman had told ESPN FC he was fine and fit to play.

Even before the injury scare, Chandler had not been scheduled to participate against Ecuador as Klinsmann added Kellyn Acosta of FC Dallas to the roster for the friendly at Toyota Stadium.

"Per regulations, an injured player may be replaced on the roster up to 24 hours prior to a team's opening match," a statement from U.S. Soccer said.

"The replacement must come from the 40-man preliminary roster submitted April 29 and approved by the tournament medical committee."

The right-back had struggled for form and fitness under the club's former coach Armin Veh, but was promoted back to the starting XI by Niko Kovac. He made only a handful of appearances in the Bundesliga this season.

Cameron, meanwhile, picked up a hamstring injury in Stoke City's final game of the season against West Ham United. As such, the U.S. has taken a careful approach to his recovery, and that looks to have paid off.

"[Cameron], he's all good, he's ready to go," said Klinsmann during Friday's media availability. "We took it one day at a time with Cam. It's not been anything difficult. We just wanted to make sure he's fully, fully 100 percent and he trained well the last couple of days. He could have gone in also against Ecuador for a couple of minutes, but he didn't want to do that."

The versatile Cameron is viewed as a critical piece to the U.S. back line, and is expected to partner John Brooks in the center of defense. The two were paired briefly at the 2014 World Cup, but haven't seen much time together since then. Cameron doesn't foresee any problems.

"We've played together before a bunch of times in training," said Cameron about his possible pairing with Brooks. "I think we're comfortable and confident with one another."

As for Chandler, a U.S. soccer spokesman said that he had been carrying the quad injury for some time, and then aggravated it during the second leg of Eintracht Frankfurt's relegation playoff with FC Nuremberg.

"We gave it a try," said Klinsmann. "We knew that [Chandler] had that issue...Then he came in, we did an [MRI] and unfortunately it confirmed a bigger injury than he hoped that it would be. We are prepared for those cases."

With Fabian Johnson and DeAndre Yedlin expected to man the outside back spots, Chandler figured to fill a backup role. Now that responsibility lies with Castillo, who as 18 caps with the U.S. team.

"It's totally logical the decision after Timmy is out, that Edgar is in," said Klinsmann. "He was aware of that. It's all good."