Anthony Rendon's availability for the Washington Nationals' season opener is in doubt after a second MRI on his injured left knee failed to reveal progress as expected.

"Opening Day is in jeopardy at this point, because he simply hasn't had the baseball activity to get ready," Matt Williams said. "Does that mean he's not ready for Opening Day, but ready four days later? Potentially. We just don't know at this point.

"It's a tricky injury, because the MRI shows no structural damage, per se. But it's something you use every day. It's on the right track. It's just a question of when he can get through the soreness and get back to [playing]."

A sprained MCL in his left knee has limited Rendon, 24, to three games and nine at-bats in the Grapefruit League this spring. He hasn't appeared in a game since March 9 because of the injury.