What Does SP, RP, and CP Mean in Baseball? (Solved!)

While watching a baseball game, you’ll often see different acronyms and abbreviations referring to various positions or plays on the field.

Some of those are rather self-explanatory and easy to understand. However, some others are less clear which can sometimes be a bit confusing.

For example, when it’s the pitcher’s turn to throw, you’ll often see certain acronyms next to the specific pitcher’s name.

So, a lot of people often wonder what does SP, RP, and CP mean in baseball?

Although it may not be obvious at first, the answer is very simple. SP, RP, and CP are just acronyms that stand for different types of pitchers.

As these designations are relatively new in baseball, it’s understandable that many fans are still not very familiar with them.

For that reason, I’ll explain what each of them means and what type of pitchers each of them stands for.

So, let’s dive in!

What Does SP Mean In Baseball?

Baseball player pitching a ball.

In baseball, the acronym SP refers to the Starting Pitcher.

This is the spot commonly reserved for the best pitchers on the team and each roster features 4-6 SPs.

This is necessary because of the high workload starting pitchers take on during the game.

While it would be ideal to always have an ace pitcher on the field, this is not possible as it would be too taxing on their bodies.

In most cases, Starting Pitchers get three to five days of rest between games.

During the game, they will usually throw for five or more innings, but rarely more than seven.

Sometimes, their involvement in a game is determined by a pitch count and most managers keep their starting pitchers in for 100 – 125 pitches.

If they are not able to perform at a high level for at least five innings regularly, SPs are commonly relegated to the bullpen.

What Does RP Mean In Baseball?

Baseball pitcher on the mound.

When we talk about baseball, RP stands for Relief Pitcher. These are the players whose job is to replace Starting Pitchers.

Depending on the role of the specific RP and the current game situation, they may pitch anywhere from one to five innings.

Starters can be replaced for a variety of reasons such as strategy, ineffectiveness, fatigue, or ejection.

Usually, every roster features 9-13 Relief Pitchers. In addition to those players, any other position can become a Relief Pitcher.

While they pitch fewer innings than starters, relievers commonly appear in more games, often on consecutive days.

In most cases, RPs have specialized roles requesting them to pitch for a certain amount of time before another reliever comes on.

This is the reason why, in baseball, we have several different types of Relief Pitchers.

Long Reliever

Long Relievers are the only exception to the rule that says relievers only play in small doses.

They commonly provide several innings of relief for various reasons.

They may enter in place of the Starting Pitcher in the first three innings if the starter is injured, ineffective, or ejected.

This allows managers to have more flexibility later in the game.

Managers also often call on them when there are extra innings and the game may last longer than expected.

In many cases, Long Relievers are former Starting Pitchers who don’t have what it takes to deserve starting spot anymore.

Still, they may occasionally start the game in place of one of the pitchers from the starting rotation.

Middle Reliever

Middle Reliever’s main duty is to bridge the gap between starter and Setup Man or Closer.

Usually, their turn to pitch comes in the sixth and seventh inning.

Middle Relievers serve to protect the lead or, if the other team is ahead, to prevent them from extending that lead.

Typically, they get pulled in eight or ninth inning, but may occasionally pitch in those innings too if there’s no save situation.

As they often come in for Starting Pitcher, they should be good at stranding inherited runners.

Setup Reliever

Setup Reliever (aka Setup man or Setup Pitcher) is the pitcher who takes the mound before the Closer comes on.

This commonly happens in the eighth inning and that’s usually the only inning Setup Reliever plays in.

They mostly come to the play in situations when the team is protecting a small lead near the end of the game.

To be successful, SUs need to leave the game with that lead preserved.

Typically Setup is the second-best among the relievers, after the Closer. Often, the best Setup Relievers are promoted to Closers.

What Does CP Mean In Baseball?

Baseball player with elbow guard pitching a ball.

CP stands for a Closing Pitcher or a Closer, who commonly pitches in the last inning.

They come in the game at the start of the ninth inning and that’s the only inning they play in.

The situation when they’re called to enter the game is usually when their team holds the lead of 3 runs or less.

Their role is to protect the lead and close the game.

CP is a special type of Relieve Pitcher and, in most cases, the best pitcher among them.

They’re usually effective against both left and right-handed batters and commonly have a superior fastball and a couple of complimentary pitches.

Besides having quality pitches in their arsenal, these are commonly pitchers who specialize in throwing under pressure which is frequent in late-game situations.

This is why Closers are highly appreciated and often have salaries on par with starting pitchers.


Using acronyms such as SP, RP, or CP is a relatively new trend in the MLB.

This is why a lot of older fans can get confused and often fail to understand what these acronyms stand for.

On the other hand, the younger generation of baseball fans is much more familiar with them.

The main reason for this is that these designations came to prominence with the rise in the popularity of fantasy baseball and baseball-themed video games, such as The Show.

Now, SP, RP, CP, and acronyms for other positions are frequently used by the players and coaches, as well as broadcasters and fans.

Once you get familiar with these terms, they make following baseball much simpler and create less clutter on our screens while watching a game.

Paul Hall
Paul Hall

Hello, I’m Paul, a 45 year old passionate baseball fan and the owner of this website. I hope my article could help to answer your questions.

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