Boston Red Sox designated hitter David Ortiz claps his hands before stepping into the batter's box during an interleague game against the Colorado Rockies at Fenway Park in Boston, June 26. Baseball's experiment to boost scoring and interest in the then-lagging American League turned 40 this year, and never has the designated hitter been more of a wedge between the two leagues than in 2013, with interleague play all season long and the potential for a pennant-race-altering effect. (AP Photo/Elise Amendola)
In this June 1, 1973, file photo, New York Yankees' Ron Blomberg heads for first after as he grounds out against the California Angels during a game at Yankee Stadium in New York. Blomberg became the first major league designated hitter in an opening-day game in 1973.