Adam Eaton, shown here during spring training, left the Nationals this week to seek a second opinion on his injured ankle. (Photo by Toni L. Sandys/The Washington Post)

SAN DIEGO — Nationals outfielder Adam Eaton traveled Wednesday to Green Bay, Wis., to seek a second opinion on his ailing left ankle from renowned orthopedic surgeon Robert Anderson, according to a person familiar with the situation.

Eaton injured the ankle on an awkward slide in mid-April. The pain continues to be a concern, especially because he sprained the ankle when he tore his anterior cruciate ligament last April. Nationals medical staff initially diagnosed Eaton with a bone bruise, but the pain has persisted.

Anderson joined the Green Bay Packers medical staff in 2017. He has worked with athletes across the major sports, including Cam Newton, Steph Curry, Kevin Durant, and Derek Jeter, according to reports.

As of late Wednesday, the Nationals did not know the results of the visit, and were not sure what the next steps would be.

The trip to Wisconsin does confirm what many around the team believe: The ankle injury, whatever it is, simply isn’t getting better. The Nationals put Eaton in a walking boot out of excess caution, immobilizing it in the hopes that inactivity would reduce the pain. He could walk on it. When he tried to run on it, the ankle ached.

Eaton missed most of last season with that torn anterior cruciate ligament. At the time of that injury, he was hitting .297 with an .894 OPS. Before the ankle injury this season, Eaton was hitting .345 with a 1.079 OPS.

In his limited time with the Nationals over two seasons, Eaton is hitting .308 — producing at a pace that would certainly seem to justify General Manager Mike Rizzo parting with three top pitching prospects for five years of his services. But the 29-year-old has not been able to stay healthy, with a visit to Anderson only the latest turn.