Baseball, by the Rules

Shortstop Xander Bogaerts (of the San Diego Padres) prepares to field a ball off the bat of Jonathan Aranda (of the Tampa Bay Rays), while Tampa's Brandon Lowe runs between 2nd and 3rd.
Infield Ground Ball
The batter hits a ground ball into the teeth of the infield defense, and runs to first. Any other forced runners also start running, while runners who are not forced figure out if they should try to advance, or stay put. The fate of these runners is now in the hands of the defense, as depending on where the ball is fielded, which runners are where, and how many outs there are, the defender is likely going to have a lot of options. More often than not, there’s a good chance that the defense can get at least one out— usually the batter running to first, but not necessarily always. And if there are multiple runners being forced to the next base, the defense has a good chance of turning more than one of those runners into outs on the same batted ball— an event known as a “double play.” But, of course, with the right circumstances, all the runners can wind up safe, regardless of how well or poorly the defense does.