Span has been on the disabled list since July 10 with tightness in his back. He recently took batting practice and fielded fly balls but didn't feel as good the next day and needed some rest.
Span said he was better Sunday but ''but I'm not over the hump yet. The pain kind of comes and goes. Something just isn't cooperating.''
He has played in all but 24 games the last two years for the Nationals but had sports hernia surgery in December and abdominal surgery in March. The 31-year-old free agent-to-be knows teams are keeping an eye on his health.