In MLB, the four-man rotation has not had success since the 1970s. The Colorado Rockies gave it a shot in 2012, but it didn’t last long. The Los Angeles Dodgers are a team that had success with a four-man rotation, highlighted by Sandy Koufax, Don Drysdale, Claude Osteen and Don Sutton starting 154 of the 162 games in 1966. The Baltimore Orioles had four 20-game winners in 1971 thanks to a dominant four-man rotation.

The idea has been seen as taboo lately though, with injuries becoming a bigger concern with larger contracts. Teams have even used six-man rotations, trying to preserve arms for later in the season. The Seattle Mariners are in an interesting situation where they could easily have a six-man rotation, but the answer might actually be to go with four.

The Mariners have four guys who are a lock for the rotation: Felix Hernandez, Hisashi Iwakuma, Wade Miley and Taijuan Walker. The list for the fifth spot is long, with Nathan Karns, James Paxton, Vidal Nuno and Mike Montgomery all having a legitimate shot at the spot. Karns, Paxton and Nuno all have options left, but Montgomery has to be on the big league roster or he will go through waivers. Montgomery is the least likely to earn the last spot in the rotation, though.

If the Mariners went with a four-man rotation, they would have another spot open in the bullpen. Paxton and Karns could head to Triple-A while Nuno and Montgomery go to the bullpen. If anything happened to one of the starters, Karns and Paxton would be willing and waiting. With four guys who are far above the rest, it is logical to want them to play as often as possible.

The Rockies went with a pitch limit when they tried their experiment, limiting pitchers to 75 pitches, but that didn’t work and is not the right approach. If you have pitchers like Hernandez pitching well, you have him pitch until you would normally pull him. If a pitcher is having a bad game though, pull him immediately. The bullpen would have eight pitchers, so they could have two bullpen arms set aside for each starter. The Mariners could use Karns, Nuno and Montgomery in the bullpen, acting as long relievers on the down games by starters.

The four-man rotation could end up being a draw to starting pitchers as well. Instead of the 33 starts Hernandez would normally have, he would have the opportunity for 42 starts. For a pitcher who has been within two wins of a 20-win season twice (never accomplishing the feat), the chance for nine extra starts would be huge. The key becomes listening to the player. If there was a game Iwakuma needed to sit because he needed some rest, then giving him that game off not only lets a bullpen arm start such as Nuno, it allows Iwakuma to have an extended break by just skipping his spot in the rotation.

The problem everyone mentions with this strategy is that it is too taxing on starting pitchers and they are not prepared to pitch with only three days off. With the way the schedule is, though, most times three days is actually four and sometimes even five. If you look at the Little League requirements for pitches and days off, you quickly see this is something that has been blown way out of proportion:

Pitchers age 15 to 18 must follow:
76 or more pitches – 4 days of rest
61-75 pitches – 3 days of rest
46-60 pitches – 2 days of rest
31-45 pitches – 1 day of rest
1-30 pitches – no rest required

There are no rules for Little League that require a player to ever have five days of rest. It becomes mind-boggling when you take into consideration how much starting pitchers get paid nowadays. Zack Greinke was just paid $206.5 million for six years (averaging $34.4 million a year), meaning if he makes all his starts, he will essentially get paid over $1 million a start by the Arizona Diamondbacks.

The Mariners could really benefit from having Hernandez, Iwakuma, Miley and Walker for 32 extra starts. It would definitely be a transition, but I honestly believe it is the future of starting pitching with the amount guys are being paid. The Mariners are in the perfect position to succeed with four strong starters and the depth needed at the position.