The opportunity presented itself as scheduled starter Tim Lincecum was scratched from the lineup due to a back strain. Lincecum is expected to make his next scheduled start.
According to Giants' GM, Brian Sabean, Bumgarner will be on a short leash if things get too sketchy for the young 20 year-old in his first major league outing.
The call-up was a bit of a surprise based on the standard dismissive answers Sabean gave previously regarding whether Bumgarner would be brought up to the big league team in previous months.
With the call-up, the Giants now have their future battery mates in place with catcher Buster Posey being called up just last week after rosters were expanded.
Bumgarner was 9-1 in 19 starts at Double-A Connecticut with 69 SO, 30 BB, 1.03 WHIP and 1.93 ERA.
The left-hander was the Giants' 1st round draft pick (10th overall) in the 2007 draft.