My younger son is a college infielder. His workouts consist of weight-lifting, running sprints, running for endurance, and long toss. With the weight lifting program, it's extremely important to include a lot of flexibility work before and after each session. The weight-lifting/running is done on alternate days. He throws, primarily long toss, about 4-5 days a week.
A lot of college baseball programs post their summer workout program on the internet, and frequently there are different programs for different positions, although it's primarily one for pitchers and one for position players. You may have to google a bit but they're out there.