Already hailed for its realistic depiction of the inner-city drug trade, HBO’s acclaimed series “The Wire,” which has been picked up for a third season, is about to get another heavy dose of street cred. Richard Price, the author and screenwriter known for his accurate and gritty portrayals of urban life in such books and films as “The Wanderers” and “Clockers,” is close to signing on as a writer on the series, according to a person familiar with the situation. The hire is in line with the series’ philosophy of telling the story of Baltimore’s drug trade, using techniques more familiar in novels than on TV. Those include requiring readers (viewers) to pay attention to details and to sit through slower-moving early chapters (or episodes), which set up the story, before the action kicks in later. While the arrival of Mr. Price, who has been called a modern-day Dickens, will likely bolster the series’ griminess, it’s not the first time the 54-year-old native of the Bronx, N.Y., has been a part of “The Wire.” Mr. Price appeared in front of the camera during the second season, leading a prison book group discussion about “The Great Gatsby.”