The pattern size of a glove pertains to the width of the glove, and therefore how well it fits your hand. It's not primarily about the length. If the glove measures more than 12 inches from the tips of the fingers to the heel of the glove, it's not legal to use for baseball. However, no umpire measures unless asked, and no one asks. Besides, if it's marked as a baseball glove, it's not going to exceed that length. Infielders typically use gloves with shorter fingers and shallower pockets to make it easier to transfer the ball. Outfield gloves typically have longer fingers to give that tiny bit more reach. So, unless the fingers are particularly long, or the pocket particularly deep, then you could reasonably use that glove at any position. Mitts are allowed at first and catcher, but a regular glove is also allowed at first, and is also legal for catching under some rules codes.