Breaking In the Marucci Cat 9. Bat Break-In Tips You Need to Know


The Marucci Cat 9 baseball bat has become one of the most popular bats in the game since its introduction in 2017. Marucci designed the Cat 9 to be a balanced, one-piece aluminum bat that provides excellent performance right out of the wrapper. Some key features of the Cat 9 bat include:

  • AZ105 alloy barrel that creates a light, responsive sweet spot
  • Ring-free barrel construction that optimizes barrel flexibility
  • Balanced swing weight
  • 2 5/8″ barrel diameter
  • BBCOR, USSSA and USA certification for all levels of play

With its reputation for being hot out of the wrapper and providing great pop, the Cat 9 has been embraced by players from youth leagues all the way up through college and the pros. It has become a favorite among contact hitters thanks to its balanced feel and alloy composition that creates excellent bat control.


The Marucci CAT9 baseball bat features an innovative alloy composition called AZR alloy. According to Marucci’s website, “AZR alloy is a stronger, lighter, and more responsive alloy” used in their metal bats like the CAT9 (“CAT9 – Metal Bats”). The CAT9 series utilizes Marucci’s AZR alloy that has been thermally treated and strengthened to increase performance and responsiveness (“CAT9 Composite | MEANER. HOTTER. BOLDER.”). Specifically, the CAT9 incorporates Marucci’s latest AZR alloy composition called AZR 2, which aims to provide a lighter and more balanced swing weight for better bat control and power.

Barrel Size

The Marucci Cat 9 comes in a variety of barrel diameter options. According to Marucci’s website, the standard Cat 9 BBCOR models are available with barrel diameters of 2 5/8 inches, 2 3/4 inches, and 2 1/2 inches (

For the composite Cat 9 models, the barrel diameter is 2 5/8 inches as listed on their site ( The Cat 9 Pastime Junior Big Barrel model specifically comes with a 2 3/4 inch barrel diameter according to the product description (

So in summary, 2 5/8 inches, 2 3/4 inches, and 2 1/2 inches are the most common barrel diameter options available for the Marucci Cat 9 models.


The Marucci CAT 9 baseball bat comes in a range of weight options to accommodate players of different sizes and skill levels. According to the Marucci website (, the bat is available in the following weight-to-length ratios:

  • -12 (12 oz lighter than bat length)
  • -11
  • -10
  • -9
  • -8
  • -5
  • -3 (BBCOR)

The range of weight options allows players to choose the optimal balance of weight and bat control. Lighter weight-to-length ratios like -12 are best for younger players or those focused on bat speed and making contact. Heavier options like -3 are preferred by power hitters looking for maximum bat momentum.

Within a given weight-to-length ratio, players can also choose different exact ounces to fine tune the bat weight. This helps dial in the optimal feel based on a player’s height, strength, and personal preference.


The Marucci Cat 9 comes with a factory grip that is made of synthetic leather. Marucci offers their Bat Grip in 1.8mm and 2.0mm thickness options to accommodate different preferences. The grip helps provide a tacky, durable feel that many players prefer. Some players choose to replace the stock grip with an aftermarket option like Lizard Skins bat grip tape. Lizard Skins offers grip tape in a variety of colors and sizes like the popular 1.8mm DSP tape. Players can find these grips on sites like Amazon and Dick’s Sporting Goods to customize the feel of their Cat 9 bat. Ultimately the grip comes down to player preference and comfort.


Break-in Methods

There are a few common methods used to properly break in a new composite bat like the Marucci CAT 9:


Rolling involves gently rolling the bat back and forth on a flat surface to loosen up the fibers and resins inside the barrel. This helps “open up” the sweet spot. According to Marucci, rolling your bat 50-100 times can help break it in without damaging it.

Soft Toss

Soft toss involves lightly hitting balls lobbed from a short distance. Start with 25-50 easy swings and gradually increase the intensity. The initial soft contact helps loosen the barrel without over-flexing it. According to JustBats, soft toss is an effective way to break in a composite bat.

Batting Practice

Taking batting practice against moderate velocity pitching allows controlled swings that continue to expand the sweet spot. Once the bat has been initially broken in, live batting practice helps finish the break-in process. According to Baseball Savings, batting practice is key for complete composite bat break-in.

Hitting Indoors

When breaking in a bat indoors, it’s important to use a batting cage or netting area with ample ceiling height and distance. This allows you to complete full swings without fear of damage. According to JustBats, a standard 3-car garage or large unfinished basement works well for indoor batting practice (source).

It’s recommended to use batting tees and soft toss when breaking in a bat indoors. Avoid hitting hard surfaces like concrete walls, as this can damage the bat and void the warranty. Focus on controlled, partial to full swings into the netting or batting cage. This allows the fibers and carbon of the composite bat to compress and break in properly (source).

Take breaks every 25-50 swings to allow the bat to rest and normalize. This prevents overheating. Rotate the bat periodically to distribute contact across the barrel for even break-in.

Hitting Outdoors

When breaking in your bat outdoors, it’s recommended to find an open space like a field or empty parking lot to allow for full swings. Make sure the area is clear of obstructions and other people. Wearing a helmet and watching out for stray balls is advised. Start with 25-50 slight hits at about 50% power to gently loosen the fibers and compress the bat. Then gradually build up to 75-100 full power swings over 30-45 minutes. Focus on making solid contact with the sweet spot consistently. Avoid hitting off artificial surfaces like metal backstops which can damage the bat. Rotate the bat a quarter turn every 5-10 hits to distribute contact evenly. Check for signs of damage like cracks or embedded rocks/debris after use. Wipe down the bat with a dry cloth to clean it. According to How To Break In Your Composite Baseball or Softball Bat, taking 150-200 full swings over a couple sessions outdoors is ideal for properly breaking in a composite bat.


Properly breaking in a new composite bat should take less than an hour of hitting. According to JustBats, it only takes around 150-200 swings to break in a composite bat[1]. Baseball Monkey also recommends 150-200 swings and says the process often won’t take more than an hour[2]. Rip It recommends no more than one hour of hitting to break in a composite bat[3].

The key is not to rush the break-in process. Take your time and allow the bat to gradually break in with solid contact over the course of an hour. Don’t try to accelerate the break-in too quickly, as that could damage the bat.


Proper maintenance is crucial for extending the life and performance of your Marucci Cat 9 bat. After each use, wipe down the barrel with a clean dry cloth to remove dirt, grass stains, pine tar buildup, etc. Allow the bat to air dry before storing. Do not use harsh cleaners that could damage the finish.

Applying a beeswax-based bat polish every 10-15 games can help nourish the wood and maintain the bat’s original luster. Let the polish sit for 3-4 minutes, then gently buff with a soft cloth [1]. Avoid over-polishing, as this can cause the finish to wear prematurely.

When not in use, store the bat in a climate-controlled environment away from direct sunlight and extreme temperature fluctuations. Keep it in a bat sleeve or wrapped in a towel – never lean it directly against a wall or fence.

With proper care, your Cat 9 can maintain optimal performance and durability for many seasons.

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