EAST RUTHERFORD, N.J. (AP) -- Two-time Pro Bowl defensive end Osi Umenyiora missed practice Monday without giving Giants coach Tom Coughlin an explanation.
Umenyiora, who missed all of last season with a knee injury, attended meetings in the morning at the team's headquarters. However, he left unexpectedly without talking to Coughlin and didn't return for the workout.
"We will have to talk to him when he gets back," Coughlin said. "Obviously he is not here, so I am concerned."
New York general manager Jerry Reese sent a text message to Umenyiora to ask him if he was all right. Umenyiora responded that he was, but didn't explain why he left.
The absence will be considered unexcused, so Umenyiora likely will be fined.
"There must have been something of a personal nature, and he left," Coughlin said. "I haven't personally talked to him. He did respond to Jerry, evidently by text. That's all I have. I haven't seen him, so I can't tell you."
After missing the last two preseason games with a sore foot, middle linebacker Antonio Pierce returned to practice on Monday.
Starting left guard David Diehl did not practice because of soreness in his kneecap. He will not play against the New England Patriots on Thursday in the preseason finale.
Also missing practice were safety Kenny Phillips (sore knee), cornerback Aaron Ross (hamstring), halfback Danny Ware (ribs), receiver David Tyree (hamstring) and defensive tackle Chris Canty (hamstring).
Backup offensive tackle Guy Whimper, who was filling in for Diehl, had to leave practice with a hip flexor after colliding with halfback Brandon Jacobs. Free agent offensive lineman Andrew Carnahan twisted a knee.
Coughlin did not know the extent of their injuries.