Mavs G Harris finally signs extension

The Dallas Mavericks signed Devin Harris on Saturday to the five-year agreement they reached earlier this month. The extension is worth about $42 million and locks up the speedy point guard through the 2012-13 season. He would have been entering the final year of his rookie contract. Harris averaged career-highs across the board last season, including 10.2 points and 3.7 assists, as the Mavericks…