Washington Nationals center fielder Denard Span will join Class A Hagerstown on Tuesday to continue his rehab assignment.

Span (back) will shift over from Class A Potomac, where he went 0-for-2 Sunday in his first game action since July 6. Infielder Dan Uggla, battling a back injury of his own, also begins a rehab assignment Tuesday at Hagerstown.

The Nationals, who have dropped six straight to fall 4 1/2 games behind the first-place New York Mets in the National League East, have missed Span's presence at the top of their lineup.

Washington is 35-24 with Span in the lineup this season and 23-35 when he sits out. Span, who tied for the NL lead with 184 hits last year, is batting .304 with five homers and 22 RBIs.