Cornerback Brian Davis appears headed for injured reserve after pulling a calf muscle last week. He was unable to play in Sunday's 41-38 overtime victory over Detroit, and that forced the Redskins to use two free agent cornerbacks -- Alvoid Mays and Sidney Johnson.

It is unclear what move the Redskins will make to replace Davis on the 47-man roster. Sources said the team was not shopping for a fifth cornerback yesterday, apparently feeling four will be enough against the Philadelphia Eagles Monday night.

That probably means someone will be brought off injured reserve this week. Five players are eligible to be activated, including quarterback Mark Rypien.

However, Rypien's earliest return still appears to be Nov. 18, when the New Orleans Saints play at RFK Stadium. He will step up his practice schedule this week, but he still may not participate in full-blown drills.

When his left knee was injured against the Cowboys in Week 3, doctors predicted Rypien would return for the Cowboys on Thanksgiving Day. He may beat that return by one game and four days. Another First for Three

Last season, the Posse became the first NFL receiving trio to have each of its members surpass 1,000 yards. Sunday, those three crossed another barrier.

Although Gary Clark, Ricky Sanders and Art Monk have been playing together since 1985, Sunday's victory over Detroit marked the first time each had gone over 100 yards in a game.

Monk caught 13 passes for 168 yards, Sanders 11 for 132 and Clark eight for 132. The 32 catches for 432 yards marked their single best day and came a week after their worst day -- four catches for 33 yards.

The last time the Redskins had three 100-yard receivers was Nov. 26, 1967, when Charley Taylor, Bobby Mitchell and A.D. Whitfield did it.

Monk is three receptions shy of becoming the third player in NFL history to catch 700 passes. He has caught passes from six different quarterbacks. . . .

The team said the time listed for the Dec. 9 game with the Chicago Bears at RFK Stadium is wrong. The game will start at 4 p.m. instead of 1.