Vogelsong and the Houston Astros had been reportedly very close to a deal, but that dramatically changed after Ken Rosenthal of FOX Sports reported that Vogelsong had "shifted course" and was in serious discussions with San Francisco. Vogelsong is a low-risk, potentially high-reward re-signing for the Giants, so this deal could be excellent for them in the coming season.
The 37-year-old Vogelsong has pitched each of the past four seasons with the Giants, earning two World Series rings with them (2012 and 2014). Last season, he pitched 184.2 innings, going 8-13 with a 4.00 ERA in 32 starts. Vogelsong's FIP was 3.85 last season, alluding to the fact that his ERA was inflated due to poor defense. He register a 7.4 K/9, a 2.8 BB/9, and a 2.60 K/BB ratios in 2014.
The Giants all of a sudden see themselves with a surplus of starting pitchers. Madison Bumgarner, Matt Cain, Tim Hudson, Jake Peavy, Tim Lincecum, Yusmeiro Petit, and now Vogelsong will compete for the five rotation spots. (Bumgarner, Cain, Hudson, and Peavy are likely locks.) In 2015, assuming Vogelsong does win the fifth spot in the starting rotation, Tim Lincecum and Yusmeiro Petit could be seen throwing out of the bullpen, which is already fairly deep. The Giants are putting themselves in a good spot.
Vogelsong's story is quite a good one. He was drafted by the Giants in the 5th round of the 1998 MLB Draft, and pitched a total of 34.2 innings for them in 2000 and 2001. He was traded to the Pirates in July of 2001 and spent the 2002 season in the minor leagues. He came back to Pittsburgh from 2003 to 2006, posting a 5.87 ERA in 274.1 innings.
By then, he was considered a lost cause, pitching in Japan from 2007 to 2009, and coming back to the MLB in 2010. He signed minor league deals with the Phillies and Angels, neither of which worked out at all. At age 33, he came back to the Giants in 2011 and was an All-Star that year, pitching to a 2.71 ERA over 30 games (28 starts). Now, he is a successful big league pitcher.