There is a reason why anime protagonist are rarely adults. As the thing that matter the most to adults is very likely money ~~also responsibility~~. It sounds pretty lame right? Even in the richer part of the world, people are working everyday just to stay alive, even if you are a professional baseball player.

Sports anime?
You can tell from the cover art that Gurazeni is not your normal sports anime. In fact it is a workplace comedy anime about the daily struggles of our protagonist Natsunosuke Bonda and his acquaintances from different walks of life. This anime is not going to give you awesome matches, a lot of the matches are lame on purpose to create hilarious situation. Being a rather realistic sports anime is kind of lame, but it's also funny at the same time.

Money, Responsibility, Opportunities and Interpersonal Relationship
The anime name "Gurazeni (グラゼニ)" is actually the combination of the words "ground (グラウンド)" and "money (ゼニ)" in Japanese. It is a reference to the famous quote "money is hidden under the pitching ground (グラウンドにはゼニが落ちている)" by former Japanese baseball pro Tsuruoka Kazuto. This quote is a thing because professional baseball player can be one of the highest-paid job in the world. However, this only applies to the top athletes. Average athletes not only have to calculate how much they earn, spent and left for retirement. They care about baseball only because they care about their salary.

And here is our protagonist Natsunosuke Bonda, who is probably the biggest salary nerd in the professional baseball scene. This anime follows Natsunosuke's daily life, showing you how the economic and social environment of Japan is when it comes to money, with his twisted values and confidence in a humorous manner. While the MC maybe playing baseball on the pitch, he is dealing with all kinds of financial and interpersonal problems as a professional baseball player at the same time. This is what I consider the biggest appeal of Gurazeni.

Side characters
Another charm of this series is the side characters. I mentioned that the anime follows the life of Natsunosuke. However, most of the time, this anime only tells stories through Natsunosuke. The stories themselves are about the people around Natsunosuke (e.g. top baseball player, ex-player, busts, bad player, commentator, manga artist). Each of them has their own situation, and difficulties in surviving.

Downside
Animation quality is bad, and CGI is used.
Characters design are not aesthetic at all, no pretty boys.

Conclusion
As long as you understand what you are watching, you're going to have fun with it. Animation took away some points, but overall an awesome Slice of Life comedy.