Barber, who has said he wants to return, rejected the original offer on March 1.
Mackler said Barber, who visited Philadelphia on Thursday, will meet with Rams officials today.
Cleveland also is trying to sign the free agent Barber. Washington hasn't made much effort to retain its other free agents.
''The Redskins are still in the mix,'' Mackler said, ''but as we go along there are more options. Every day that goes by, in my estimation, there's less and less chance that [Barber would return]. . . .I feel real good about where we're heading. I thought this would have been wrapped up by Friday, but now it will probably go past the weekend.''
If Barber leaves, he would join center Cory Raymer and tight end Stephen Alexander, both of whom signed with San Diego, and end Kenard Lang as ex-Redskins. John Keim covers the Redskins for The Journal Newspapers.