Arrington was hurt on a wet practice field as the Redskins returned from a four-day, bye-weekend vacation.
"I think he just kind of slipped on the grass out there," coach Joe Gibbs said.
Arrington had surgery on the knee Sept. 23. He was optimistic that he could use the extra week of rest during the bye to return for Sunday's game against the Green Bay Packers.
Arrington took the field in full pads Monday, but his injury prompted yet another trip to see a doctor before practice ended.
"I don't think it's much of a setback, but we'll see," Gibbs said.
In other Redskins injury news, kicker John Hall (strained groin) missed practice and remained day-to-day. Linebacker Mike Barrow (tendinitis) also did not practice, and the team is considering shutting him down for the season.
In addition, four-time Pro Bowl cornerback Charles Woodson was
having an MRI exam Monday for a hip pointer and his status was
Defensive tackle Ted Washington has bruised ribs, but coach Norv Turner was
optimistic he might be able to play Sunday at San Diego.
Coach Bill Parcells said the injury won't require surgery but is "pretty severe."
Glenn aggravated his foot in the first quarter of Sunday's 41-20 loss at Green Bay. He had just one catch for 6 yards in that game,
and has 24 for 400 yards this season.
Morgan would be the likely replacement for Glenn in the starting lineup. He had four catches for 76 yards against the Packers.
Coach Mike Holmgren said results of an MRI exam Monday weren't
immediately known. No timeline was definite, but Holmgren said the
fifth-year pro is "probably going to miss a few weeks."
"It's pretty sore," Holmgren said. "If it's the high ankle,
typically they last longer. ... Let me just say he's doubtful right
The linebacking corps has been depleted after injuries to
starting outside linebackers Anthony Simmons (shoulder) and Chad Brown (broken leg). Seattle gets a boost when Brown, who declined
interviews Monday, returns this week.
Glenn, a standout on special teams, was injured in a 13-7 loss to the Patriots on Sunday.
Coach Herm Edwards also said Monday that nickel back Derrick Strait (foot) and middle linebacker Sam Cowart (knee) would try to practice this week and are questionable for next Monday night's
game against Miami. Right guard Brandon Moore, who has missed two straight games, is still questionable with a strained hamstring.
Green, who signed a five-year, $16 million contract in the
offseason, lost his starting job at weakside linebacker last week
for being late to a meeting during the bye week.
"I'll declare (Green's) status once we begin the week,"
Coughlin said Monday. "Once we have a chance to sit down and talk
about it, once I have a chance to look at Minnesota. I'll be glad
to talk to you about that on Wednesday."
Green refused to say anything meaningful about his status on
The 6-foot-3, 270-pound Owens was in his third season with the
Lions. He has five career catches, all in his rookie season of
2002, and had been inactive for all six of the Lions' games this
Kashama, an undrafted free agent, made the roster based on his
performance in training camp. He played two games with the Bears
Information from The Associated Press was used in this report.