Hitting fourth in a Major League Baseball lineup comes with a simple job description: drive in runs. Whether that comes from hitting the ball over the fence or just finding enough grass to evade defenders, the cleanup man is largely responsible for the team’s offensive production.
Of course, driving in runs is dependent on the guys in front of you getting on base. For some portions of Mariner history (see: 1993-2003), that wasn’t much of an issue. For other periods (see: 2010-13) it was a vast hellscape of one and two hitters who couldn’t get on base and middle-of-the-order guys who probably wouldn’t have knocked them home anyway.