Nats CF Denard Span (back) has setback; Dan Uggla (back) to DL

WASHINGTON -- Nationals center fielder Denard Span has experienced a setback in his rehabilitation from a back injury that will delay his return from the disabled list.

Span, sidelined since July 7, had been hitting, running and working in the outfield recently. He felt good at first, but manager Matt Williams said Saturday that Span's back stopped getting better.

Williams said Span will stay with the team in Washington for the next few days and then go to Florida early next week for more rehab work.

In other news, the Nationals placed backup second baseman Dan Uggla on the 15-day disabled list with back spasms.

The move opened a roster spot for right-hander Stephen Strasburg, who came off the DL to start Saturday night against Colorado. He had been sidelined with an oblique injury.