PITTSBURGH — A pit bull owned by Pittsburgh Steelers linebacker James Harrison bit his 2-year-old son in the thigh, but the boy is expected to recover though he remained hospitalized Friday, the player's agent said.

Harrison's agent, William Parise, told The Associated Press that James III was bitten after his mother let the dog out of its pen Thursday afternoon. Parise wouldn't identify the woman, but said she and Harrison's massage therapist also were hurt trying to help the boy. The massage therapist needed three stitches, Parise said.

Parise said Harrison was not home at the time, but was nearby and alerted after the dog attacked. Parise has not spoken to the boy's doctors, but Harrison told the agent his son likely will be hospitalized another day or two.

Parise said the boy's injuries were "serious but certainly not life-threatening. I think any time a child is injured and requires hospitalization, it's a serious thing. I know James was very concerned about his son."

The dog was removed by an animal control agency.

Burt Lauten, spokesman for the Super Bowl champion Steelers said the team is "aware of this unfortunate situation. We express our concern for his family and hope that everyone involved makes a complete recovery."

A Franklin Park police spokeswoman on Friday said police are not commenting because the incident remains under investigation.

Parise said Harrison's son is at UPMC Children's Hospital of Pittsburgh. A hospital spokesman said the family does not want information released.

Harrison lives about 15 miles north of the city.

Parise said Harrison has not had trouble with the animal in the past.

"I've been with that dog personally, he's a wonderful animal," Parise said.

Parise said he doesn't know why the boy's mother let the dog out of the pen, other than to say he believes it was for a routine reason such as feeding or to care for the animal. The boy's mother does not live at the house, Parise said.

"There's no reason to believe that this is anything other than something that sometimes happens to children," Parise said. "The child should be fine."

Harrison is the NFL Defensive Player of the Year and scored on a 100-yard interception return in the team's 27-23 victory over Arizona in Super Bowl XLIII. He made headlines for declining to join the Steelers on a White House visit Thursday, though he passed up the same opportunity after the Steelers beat Seattle in Super bowl XL in 2006.

In 2006, then-Steelers linebacker Joey Porter was cited by police in Pine Township, another suburb north of Pittsburgh, after two of his dogs got loose and killed a miniature horse on a nearby farm. Northern Regional Police said then that Porter's dogs were licensed in his hometown of Bakersfield, Calif., but not in Allegheny County.

A woman who lives a few houses down from Harrison said his dogs are well-behaved and cared for and are not a problem for neighbors.

"I jog and I run past his house every day and I have never had any problems with that dog whatsoever," said Marissa Posteraro, 19. "I have never seen the dog or heard the dog bark or whatever so I was very surprised to find out that happened."

"The dog is very well kept. It's never gotten loose before that I know of," she said.