Theo Epstein's contract expires tonight at midnight, but the 31-year-old general manager won't be looking for a new place to work for at least three more seasons. Epstein and the Red Sox have agreed to an extension of that length, keeping the Brookline native in place as the team's GM through the 2008 season, according to multiple major league sources. It is believed that Epstein, who made $350,000 last season, ranking him near the bottom of baseball's GM pay scale, will have the chance to make close to what he was seeking ($1.5 million per year). That would position him among baseball's best-compensated general managers. When the most recent round of negotiations began, Epstein received an initial offer of about $850,000 per year and a second offer of $1.2 million per year, both of which he rejected.