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6/30/2014 7:11 P.M. ET

Harper: By the numbers

WASHINGTON -- After missing 57 games with a torn left thumb ligament that required surgery, Bryce Harper returned to the Nationals' lineup for Monday's series opener against the Rockies, batting sixth and playing left field.

Harper's short time in the big leagues has been filled with hype, controversy and production uncommon for a player his age. Here's a look at some of the numbers:

1: Games prior to Monday in which the Nationals had their Opening Day lineup together. That would be on Opening Day, March 31, against the Mets, when catcher Wilson Ramos left with an injury. Since then, Harper has been one of five starting position players to spend time on the disabled list, along with two members of the starting rotation.

3: Outfield positions Harper could potentially play for the rest of the season, as manager Matt Williams uses a full roster to give players days off. Harper started in left field on Monday, with Ryan Zimmerman shifting back to third base, Anthony Rendon to second and Danny Espinosa to the bench. But Harper could also spell Denard Span in center or Jayson Werth in left.

2: Nationals with more than 36 plate appearances who have a better on-base-plus-slugging percentage (OPS) than Harper this season, though his .773 mark rests solidly below his career mark. Since the start of 2012, Werth is the only Nationals player with a better OPS than Harper's .829.

4: Hits Harper picked up in his last seven at-bats before the injury occurred on April 25. In those two games, he produced a double, a triple and four RBIs.

22.8: Harper's ratio of of at-bats to home runs during his first two seasons. In 2014, he has hit one in 83 at-bats, including an active 63 at-bat homerless streak, entering play Monday. However, he showed on his Minor League rehab assignment that his power is intact, going deep four times in 14 at-bats, including a three-homer game on Saturday for Double-A Harrisburg.

3: Players younger than Harper (21 years, 8 months, 14 days) who have appeared in a Major League game this season: the Rangers' Rougned Odor and Luis Sardinas and the Twins' Jorge Polanco.

43: Harper's career home runs, tied for 18th-most all-time through a player's age-21 season. If he could hit 13 more this season, he would move into the top 10, tied with Giancarlo Stanton and Bob Horner.

9: Players since 1950 who had a better OPS+ than Harper's 125 through their age-21 season (minimum 1,000 plate appearances). OPS+ is adjusted for ballpark and era, with 100 representing league average. The names ahead of Harper: Mike Trout, Eddie Mathews, Mickey Mantle, Frank Robinson, Ken Griffey Jr., Alex Rodriguez, Tony Conigliaro, Orlando Cepeda and Al Kaline.

5: Players all-time with more wins above replacement than Harper had through age 20, as calculated by Baseball-Reference.com. Only Trout, Mel Ott, Ty Cobb, Kaline and Rodriguez topped Harper's 8.6.

Andrew Simon is a reporter for MLB.com. Follow him on Twitter @AndrewSimonMLB. This story was not subject to the approval of Major League Baseball or its clubs.