A box score adds up as neatly as an accountant's ledger. For every 'HR', 'W', or 'K' in a hitter's column, there is an accompanying mark for the pitcher. For every winner, there is, a loser. So when Baseball America rated the MLB players with the best tools (Fastest baserunner! Best outfield arm! Best fastball!), someone had to balance the baseball universe by determining which players had the worst tools (Slowest baserunner! Worst outfield arm! Worst fastball!). It wasn't easy assembling a panel of meanies. ``You've got the wrong guy,'' one NL scout said when approached for the task. ``It's usually my job to defend guys.''