EAST RUTHERFORD, N.J. -- 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.
A league source confirmed a Newark Star-Ledger report to ESPN.com's Matt Mosley that Umenyiora skipped practice after getting into a dispute with new defensive coordinator Bill Sheridan. Sheridan, the former linebackers coach who replaced Steve Spagnuolo as coordinator, reportedly criticized Umenyiora for making a mistake in Saturday's game against the Jets.
Umenyiora surfaced later in the evening and issued a statement.
"I made a mistake by leaving the facility today," the statement said. "I was wrong. I came in here this afternoon and met with coach Coughlin, coach Sheridan and coach [Mike] Waufle and apologized and explained why I left the building; that will remain between us. I have no problem with our defensive coordinator Bill Sheridan or any of our coaches. That's the end of it, as far as I am concerned."
Earlier Monday, Coughlin had said: "We will have to talk to him when he gets back. Obviously he is not here, so I am concerned."
Later Monday night, a source told ESPN's Adam Schefter that Umenyiora had spoken to Coughlin and that he would return to the team on Tuesday.
After the defensive end didn't show for practice, 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 had said before speaking to Umenyiora. "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.
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.
Matt Mosley covers the NFC East for ESPN.com.