After months of concern, it turned out Megan Rapinoe's Olympic fate was an easy call.

U.S. national team coach Jill Ellis named Rapinoe to the 18-player squad for next month's Summer Olympics, even though the midfielder has not played in a match since tearing the ACL in her right knee in December.

The announcement came after Rapinoe, a finalist for the Golden Ball as the U.S. won the Women's World Cup last summer, returned to full training last week ahead of the Americans' 1-0 friendly win over South Africa on Saturday in Chicago.

When it comes to a player of Rapinoe's quality, that's all Ellis needed to see.

"With Megan, we got her into contact, she played, and I think that's the important piece: Are they willing to take a tackle?" Ellis said. "Megan does have an impact in terms of what she can give us on set pieces and her crossing — she's one of the best crossers in the world. So there were certain qualities in there that if I felt we could utilize them enough, if she was indeed healthy to play, that we could use that."

Rapinoe likely made the squad at the expense of veteran winger Heather O'Reilly, who leads active U.S. players with 230 caps and was hoping to win a fourth straight Olympic gold medal.

Although Ellis said O'Reilly was disappointed to miss out on the 18-player squad, the 31-year-old has embraced her role as one of four alternates who will travel with the team to Brazil.

"She was the utmost professional," Ellis said. "With these players, you don't know that they want to be alternates. You hope they do. But in terms of with Heather, I just said, 'Are you prepared for this role?' And she goes, 'For sure, of course.' It was a phenomenal response."

Unlike the World Cup, which requires teams to lock in their rosters before their first game, the Olympics allow alternates to replace injured players during the competition. Ellis noted this rule creates a safety blanket of sorts, allowing her the flexibility to call upon a different player should Rapinoe suffer a setback during the tournament.

The plan, however, is for Rapinoe to develop form and fitness over the course of the Olympics. It's the same approach the U.S. took with Alex Morgan last summer, when the striker came off the bench for the first two World Cup matches while recovering from a left knee contusion before starting the final five matches.

"Many, many years ago, when you named alternates and they wouldn't travel with you, I think you're dealing with a small roster," Ellis said. "Now you travel with these alternates which you can replace at any time obviously if it's a medical situation, so you have it in your back pocket. Hopefully you don't need to use that, but I think the plan for Megan is to build her in this tournament much like we did with Alex."

Rapinoe recently suffered a minor quad strain while working on corner kicks in training, preventing her from taking part in Saturday's friendly. But she seems poised to participate in the send-off match against Costa Rica on July 22 in Kansas City, Kansas, with Ellis feeling confident the player can contribute to the Americans' run at a fourth-straight gold medal.

"It was a tough decision in terms of, 'Would she be back in time to contact?'" Ellis said. "Once I saw her in contact, it wasn't a hard decision."