The following is the description from the SimYard website
SimYard is your chance to own a baseball team. Each month brings a new season and a new chance to take the pennant. Each month brings a new opportunity for you to train your players how you want to train them. You choose your opponents. You choose your pitcher and your lineup. You play to win.
In SimYard, your players are your own, and you control their destiny. Train them how you want to mold them into a power hitter or a great fielder. Sign them, put them on the team you want, or trade them for different talent. You are in control, and your team is what you make it.