Bullpens have become bloated as teams have relied less upon tired starting pitchers to go a third time through the lineup and increasingly turn to a parade of fireballing relievers for the second half of the game. This has had a big impact on depressing offense, and has reduced the star power of starting pitchers.
To combat this, Major League Baseball has proposed limiting the number of pitchers on a 26-man roster to 13. This was supposed to go into effect for the 2020 season, but was shelved due to the pandemic. Again, it was supposed to go into effect this season, but was put on hiatus due to the shortened spring training.