Harper said Saturday before Game 2 of the National League Division Series against the Chicago Cubs that he'll feel more comfortable the more at-bats he gets.
He's 4-for-22 with two walks since returning, counting his 1-for-4 showing in Washington's 3-0 loss in Game 1 Friday.
The 24-year-old missed 42 games with a bone bruise in his left knee after hyperextending it Aug. 12, when he slipped on first base.
Harper came up just short of catching a run-scoring line drive in right field during Game 1 but said he felt great and that he missed opportunities at the plate.
Harper played just five regular-season games and likened it to spring training and getting back into a rhythm of seeing live pitching.