Have schedules ever been so tight, and games needed to be played that MLB has had to schedule a triple header?
There has been only one triple header in baseball history. IIRC, it occured early in the last century, but I can’t remember off the top of my head when it happened.
In any event, Rule 4.13(a)(1) clearly states that teams cannot play three (or more) games on one day. However, they can complete a suspended game and then play a double-header.
Zev Steinhardt
Wow. Six minutes for what I thought would be a fairly obscure event. You da man, zev.
Oh, and go Royals.
On the other hand, there was once a 26 inning game and that’s pretty close to a tripleheader.
A factoid: during one of the war years, 1944 I think, the Phillies played 44 doubleheaders. Since the season was only 154 games, that means that 4/7 of their games were in doubleheaders. Since 1970 scheduled doubleheaders have grown rarer and rarer and have now (I think) completely disappeared. Makeup doubleheaders still exist but are also fairly rare for a number of reasons, including the fact that umpires are instructed to wait nearly forever before calling a game. In the 40s, they waited a half, 3/4 hour and that was it. I remember one game that I went to here in Montreal that started at 1:30, was interrupted twice for an hour or two and finished after 8. I was not there at the end and I don’t suppose very many were. We have a roof now, but the result of this was that for many years I would not buy tickets in advance and I would not go to a game unless the weather was perfect. Now, alas, with fewer than 10,000 at almost every game and sometimes fewer than 5,000, there is again no reason to buy in advance.
Yes, that was on May 1, 1920 which, (if I may plug my own thread) was on my list of games that I wanted to see. The great thing about that game was that both pitchers went the entire 26 innings before the game was called on account of darkness.
Zev Steinhardt
There are still teams that schedule doubleheaders, but they are increasingly rare. The Twins scheduled one last year.
What’s even rarer now is the true doubleheader, such as the ones the Cubs-Dodgers and Padres-Pirates had on Sunday. More and more teams are opting for the day-night doubleheader with two separate admissions.
The Red Sox almost always use that because they don’t wish to lose the gate. Cleveland used them a lot in the past years because every game was sold out and if a game were cancelled, they would have to refund a whole stadium worth of admissions as there would be no way to make good.
Players hate day-night doubleheaders even more than regular doubleheaders.
Of course, this year Cleveland would only have to refund about $1.98 
Unfortunately, I have no cite, but I’m sure I remember reading that there was a tripleheader once involving the Astros (so it couldn’t have been more than 30 or so years ago). I recall it being the answer to a trivia question, “What was the only tripleheader?” though, so I don’t know where the 1920 one fits in to all of this. I’m positive I read about one with the Astros, though. Maybe it was a continued game plus a doubleheader?
I don’t recall the Astros ever playing in three games in one day. They would need a suspended game first and those are fairly rare. The Astros had one back in 1999 I believe when manager Larry Dierker had a seizure during a game.
Suspended games are fairly rare although there were two last season, both caused by electrical failures (one in Milwaukee and one in San Diego). And doubleheaders are even rarer. I would think that umpires would be loath to suspend a game if they knew that the only time they could make it up would be before a doubleheader. After all, the umpires would have to work that triple header too!