Washington Nationals left fielder Bryce Harper will be activated from the disabled list Monday, and start in left field Monday night against the Colorado Rockies, reports MLB.com's Bill Ladson:

Harper hasn't played a Major League game since April 25, when he tore an ulnar collateral ligament in the left thumb while sliding headfirst into third base against the Padres. However, Harper did played five Minor League games this past week and went a combined 9-for-14 [.643] with four home runs and 10 RBIs for Class A Potomac and Double-A Harrisburg. His best game came Saturday, when he hit three home runs for Harrisburg. Harper had the day off Sunday.

Harper's return, Ladson writes, means that Ryan Zimmerman will shift back to third base from left field, Anthony Rendon will move from third to second, and Danny Espinosa will head to the bench. And those moves will test the resolve of the second-place Nationals, who trail the Atlanta Braves by half a game in the National League East, and who boast the division's best run differential at +39:

It will be interesting to see how this arrangement works out, as Zimmerman, who has won a Gold Glove at third, said recently that he is more comfortable in left field and that Rendon is the best man to play third base. Rendon has been playing Gold Glove-caliber defense at third.

More goodness from Ladson: the Nationals hit .237 with a .304 on-base percentage without Harper, but went 30-27 without the 21-year-old.

Harper was hitting .289/.352/.422 with one home run and nine RBI in 22 games and 83 at-bats before he was hurt.

Harper's return, though, won't mean Zimmerman's days in left field are over, according to Ladson's source:

The source also said that some of the starting players will rotate on occasion. Not only will Zimmerman play third base, he will continue to see playing time in left field and at first base. Harper could see time in all three outfield spots, while Span and Jayson Werth could get days off.

The important thing is: one of baseball's brightest stars is set to return to a Nationals team that is 16-11 in June, and in the hunt for a division crown heading into July.