"I was on my way to do a physical in Chicago," Grant said. "Agreed to Washington. Told the driver to turn around and take me to the airport."
Grant said he arrived late Tuesday and signed with the Redskins on Wednesday morning, joining a banged-up backfield that didn't have a healthy alternative to rookie starter Alfred Morris.
"This time of year you need guys that have a little bit of experience, are mentally pretty sharp," coach Mike Shanahan said. "I think he's a guy in a couple of weeks' time probably could learn the system fairly quickly and help us."
Grant spent five years with the Green Bay Packers but has been looking for work since the team opted not to re-sign him after last season. He rushed for 1,203 yards in 2008 and 1,253 yards in 2009 before suffering a season-ending ankle injury in the 2010 regular-season opener. He returned last year and ran for 559 yards, sharing the load with James Starks.
To make room for Grant, the Redskins placed running back Roy Helu Jr. on injured reserve.
Helu has been dealing with turf toe in his left foot since the season opener and also has two sore Achilles tendons from training camp. He had only two carries for 2 yards and seven catches for 45 yards this season.
Helu said the injuries forced him to play in pain and kept him from practicing at full-speed. He wore a protective boot on his left foot in the locker room Wednesday.
"I don't like not playing football," the second-year back said. "I'm still processing sitting out a season."
The Redskins' only other running back, Evan Royster, was limited in practice Wednesday after spraining a ligament in his right knee in Sunday's loss to the Cincinnati Bengals. The team originally announced his injury as a strained patellar tendon. His status is uncertain for this week's game against the Tampa Bay Buccaneers.
The Redskins considered bringing back Tim Hightower, who was cut at the end of preseason after a slower-than-hoped recovery from a torn ACL a year ago. But Shanahan said Hightower had a setback in rehabilitation and could be having arthroscopic surgery on the knee.
LT Trent Williams (bone bruise in right knee) was limping and did not practice Wednesday. ... CB Cedric Griffin (hamstring) also did not practice. ... WR Pierre Garcon was limited again with a right foot injury that has sidelined him since his 88-yard touchdown catch in the season opener. "It's nagging a lot more than anybody would have expected," Garcon said. ... S Brandon Meriweather (sprained left knee) was limited.