When the Cubs' new bosses talk about the parallel tracks of building the organization from below while trying to win at the big-league level, Starlin Castro is the man with one foot on each track. And the Castro Express continues full speed into the season. Manager Dale Sveum has made Castro the No. 3 hitter, so the Cubs can start to build their lineup around him for years to come. ''Yeah, I know the stats,'' said Sveum, referring to Castro's .225 average and .571 OPS in 187 career plate appearances in the 3-hole — all last season. ''It's a commitment I made. He's still the best hitter on the team, and sometimes for the future of the team, too, you have to do it. Like I said early in camp, when do you do it to a good young hitter? Does anybody really know that answer?