Updated at 4:36 p.m.
An already disastrous week for the Nationals was dealt yet one more blow Sunday afternoon when Bryce Harper was forced out of the club's series finale in Miami following a first-inning collision with second baseman Derek Dietrich, though the initial prognosis for the 22-year-old slugger was encouraging.
Harper was suffering from dizziness but passed all concussion tests after being removed from the game for precautionary reasons, manager Matt Williams told reporters in Miami. He'll be re-evaluated before Monday's series opener in Philadelphia.
The collision occurred as Harper was rounding second base on Jayson Werth's soft grounder to short with two outs in the top of the first. Marlins shortstop Miguel Rojas only had one realistic play, and he took it, throwing across the diamond to retire Werth and end the inning.
Harper, perhaps sensing the throw might be late, went hard around second in an attempt to swipe another base. Dietrich, though, went to cover the bag himself, even though there was no play to be made, and got in Harper's way, leading to the collision.
Dietrich was playing in only his second game of the season at second base, having spent 35 games in left field, 22 games at third base and two more at first base.
Harper was on the ground in pain for a couple of minutes but eventually got up to his feet and appeared to be asking Williams and head athletic trainer Lee Kuntz to let him stay in the game. He wound up walking off the field under his own power once told he couldn't continue.
Harper, the odds-on favorite to win NL MVP honors, is only the latest significant member of the Nationals to suffer an injury this week. First baseman Ryan Zimmerman strained an oblique muscle at the start of the week and has missed the last five games. Center fielder Michael Taylor has been dealing with a nagging knee injury and has been forced to miss a few games over the last two weeks. And reliever Drew Storen broke his right thumb slamming his locker door shut after giving up a home run to Yoenis Cespedes during Wednesday night's loss to the Mets and will miss the season's final three weeks.