Villar's contract was purchased from Triple-A Sacramento on Monday.
The Giants are down a couple infielders at the moment, so they decided to give Villar a shot to show what he can do at the top level. Villar is not a heralded prospect, but he certainly earned a call-up by posting a 1.043 OPS over 66 games with Sacramento. He will not have to wait to make his big-league debut, as he will man the keystone and hit seventh in Monday's game against the Diamondbacks.