Baseball

One of my hobbies is baseball. I'm a big fan of a team called "Chiba Lotte Marines" and I often go to the stadium to watch their games. However, these days they haven't been able to win somehow. Even if they gain lots of points (like 7 points or so) by the 8th inning, the opponent team gets more points and we lose. I've seen these kinds of games so many times and feel sad...I wish the players, especially the relievers and closers (?), would gain confidence again so the team could win again.

Note: Do you mean that you're interested in baseball but don't play it? If so, I would say "One of my interests is baseball". Saying "my hobby is baseball" implies that you actually play it.

私の趣味の一つは野球です。千葉ロッテマリーンズのファンで、よくスタジアムに観戦に行きます。しかし最近なぜか勝つことができません。８回までにたくさん点をとっても、敵チームが逆転して結局負けます。このような試合をもう何度も見ているので悲しくなります。選手（特にリリーフやクローザー）が自信を取り戻し、チームが勝つことを祈っています。

Baseball

One of my hobbies is baseball. I'm a big fan of a team called "Chiba Lotte Marines" and I often go to the stadium to watch their games. However, these days they haven't been able to win somehow. Even if they gain lots of points(like 7 points or so) by the 8th inning, the opponent team gets more points and we lose. I've seen these kinds of games so many times and feel sad...I wish the players especially relievers and closers (batters and fielders??) would get confidence again and the team would win again.

私の趣味の一つは野球です。千葉ロッテマリーンズのファンで、よくスタジアムに観戦に行きます。しかし最近なぜか勝つことができません。８回までにたくさん点をとっても、敵チームが逆転して結局負けます。このような試合をもう何度も見ているので悲しくなります。選手（特にリリーフやクローザー）が自信を取り戻し、チームが勝つことを祈っています。

Just a comment on pluralisation. If you say "I've seen this kind of game...." its OK or "I've seen these kinds of games..." its also OK, but the plural or singular ending needs to follow on each word in the same context.

Great paragraph though, pretty natural sounding!