Major League Baseball rules state that a bullpen cart must be offered equally to both the home and visiting pitchers and must not allow pitchers who use it any additional time to warm up. Many teams from the rest of the league began using carts to bring pitchers on to the field during the '60s, '70s, and '80s.
The Indians were the first to use a bullpen vehicle - a "Little Red Wagon" in 1950 - and by the mid-1960s, much of the league had some sort of transportation for relievers to ride in on. Numerous old bullpen carts are preserved at teams' stadiums, but we haven't seen them in action in a long while.
The D-Backs entered the league after the bullpen cart was phased out, but they're reviving it celebrate their 20th anniversary. That's where Mark Sofia stepped in, though. "We think the time is right to bring it back".
The Diamondbacks' carts will come from the bullpens onto the warning track, head down the first- and third-base lines and stop at the dugout. He built carts for the Red Wings and the Vancouver Canadians (a Toronto Blue Jays' A-ball affiliate), and then teamed up with the Diamondbacks to create this new one.
BC-BBN-Diamondbacks-Bullpen Cart, 1st Ld-Writethru, 130Diamondbacks bringing back the bullpen cartEds: APNewsNow.
But for now at least, it looks like the Diamondbacks are standing alone there. In other words, this will be the first time the team will have the opportunity to drive its relievers in from the bullpen. But it's cool to see even this limited comeback, and maybe it will lead to more bullpen carts in the future.