But Roberts said the swelling has gone down and Seager is moving around better.
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"We're pretty optimistic for Opening Day," said Roberts. "He's doing well. He's been a very good patient."
Seager said the pain is gone "for the most part," enough that he received clearance on Friday to start playing catch. He said he'd have to accept it if he's not ready to open the season, but "that's not how I'm thinking now."
Seager was injured stopping after taking a big turn around first base on a single. He said it was the first knee injury he'd ever had.
With Seager out, Kiké Hernandez has received the bulk of playing time at shortstop.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.