My oft-stated prediction for this year’s American League East is that all five teams are going to win 84 games and then be whisked off to Omaha for a College World Series-type double-elimination tournament to determine who makes the playoffs. It’s part serious baseball analysis, part second-rate lounge act, but you get the idea: We could have a really, really bunched-up American League East this season, the races so tight that every mishap, injury or botched managerial decision could determine which teams go to October and which teams go back to the drawing board. This is why, when Red Sox manager John Farrell left the door open yesterday over the possibility of kid outfielder Jackie Bradley Jr. making the Opening Day roster, it was big, big news. Ditto with the daily updates on David Ortiz and his faulty, balky wheels. In a division race that could be so tight that aging New Englanders find themselves daydreaming out the 1967 “Impossible Dream” Red Sox, Big Papi’s absence or little Jackie’s presence could mean the difference between 78 wins . . . and 84 wins.