The situation largely dictates what you should do as a middle infielder when holding a runner at second base.
When you want to keep the runner somewhat close to the bag, you need to make sure that you’re not standing on the bag like a first baseman would. Make sure to be in an athletic position, which will allow you to make a play at second on a throw from the pitcher, or to quickly field a ball that is hit toward you.
Before the pitch, you should creep towards the runner in a spot where the pitcher can see you. If you want the pitcher to pick off the runner, flash your glove and keep moving to second base so the pitcher can turn and throw to the bag.
If the pitcher doesn’t want to pick the runner off, but keep them close to the bag and aware of his presence, you should creep towards the runner and then quickly move back into position. As the pitcher sees you move back into position, he should deliver the ball to the batter. Remember to be in a good fielding position when the ball reaches the hitting zone, ready to move to either side to make a play. Regardless, you should always be prepared if the pitcher wants to pick the runner off the base.
As an infielder, the key is to make sure that you are not providing the batter with a big hole when the pitch is thrown. The main focus is to keep the runner close to the base while being prepared to make a play on a ground ball.