Major League Baseball teams are more invested in their players today than ever before. In 2015, player salaries jumped to an all-time high of over $3.5 billion, a raise north of $320 million (and over 10 percent) from 2014 alone. And now that they give out contracts of upwards of $30 million a year, teams are more protective of their starting pitchers today than in the past. That has led to fewer complete games and more innings limits.

Focusing on the last 31 seasons, from 1985 to 2015, I looked to see how drastic this trend has become. I also limited the study to pitchers with at least five starts and no more than two relief appearances to limit it to full-time starters. The below graph illustrates the declining length of starts year by year for our specified group of pitchers.

As you can see, the average length of a start was roughly 6 2/3 innings pitched per game started in 1985. Last year, the average length of a start was down to a tick above 6 innings, which is an all-time low. That trend does not necessarily indicate that teams are relying on their starters less and less. It’s possible that an increase in offense could have created the trend with pitchers needing more pitches per inning, leading to a shorter average start. However, a look at the change in ERA by season, a proxy for offensive change, suggests otherwise.

This graph highlights the steroid era, likely peaking in 2000 with a 4.61 ERA. However, recent seasons show cooling offenses. In 2014, the 3.57 league ERA was the lowest since 1989. As such, the decreasing average length of starts must reflect a change in how teams use starters as opposed to a change in the context of their use.

When you combine the decreasing length of starts with the dramatic increase in player salaries, the average price per inning pitched has skyrocketed over the last three decades.

In 1985, Major League teams paid just under $3,000 per inning in each game started. In 2015, that number was nearly $50,000 per inning. And while there may be factors other than the increasing salaries of pitchers such as the rise in Tommy John surgeries and teams’ increasing reliance on analytics, the offensive environment does not seem to be one of them. Or…maybe offense is on the rise?