During Monday's game between the Giants and Nationals, a pitch broke Ryan Vogelsong's right hand. Despite requiring surgery, San Francisco expects Vogelsong to return to the starting rotation within two months.

Before this season began, most baseball people believed the Giants would have the best starting rotation in the National League. After all, their rotation helped them to become World Series champions in both 2010 and '12.

So far this season, San Francisco's rotation has the third-highest ERA in the NL. The team was counting on having great starting pitching to be competitive in the NL West. Despite the unexpected rotation problems, the Giants are tied with the D-backs and Rockies for the division lead.

It's difficult to believe a starting rotation featuring Vogelsong, Matt Cain and Tim Lincecum has struggled. However, it has. Except for Madison Bumgarner and Barry Zito, the starters haven't performed anywhere close to what anyone expected.

Unlike the Dodgers' starting rotation that has been decimated by injuries, before Monday, the Giants hadn't suffered an injury to a starter.

At the time of Vogelsong's injury, he was pitching his best game of the season. On Tuesday, Cain performed as everyone thought he would coming into the season.

While the starting rotation has had problems, San Francisco's bullpen has been fantastic. Usually when the starters allow many runs, they don't stay in a game for long, putting more stress on the relievers. The relievers appearing in too many games get exhausted and ineffective. So far this season, that hasn't happened to the Giants. Their bullpen has the second-lowest ERA in the NL.

Although the Giants' wonderful defense helped them sweep the Tigers in the 2012 World Series, they have the second-worst fielding percentage in the NL. This definitely hasn't helped the struggling starting rotation. It also wasn't what general manager Brian Sabean envisioned when he built this team, keeping almost the same roster as last season. If San Francisco doesn't improve its defense, the Giants can't maintain their position as one of the elite teams in baseball.

Surprisingly, the Giants have had excellent offensive production, the only area that has kept them at the top in the NL West. They have scored the fourth-most runs in the NL. They still are near the bottom of the league in home runs. However, their on-base percentage is third and they don't waste many scoring opportunities. Their batting average is the best in the NL.

Bruce Bochy has always been a manager who understands the importance of manufacturing runs. He mostly hasn't managed in hitter-friendly stadiums, so when his team has a scoring opportunity, he will do everything in his power to have them take advantage of it.

When the season began, most baseball people expected the Dodgers would challenge the Giants for the lead in the NL West. The Dodgers have suffered many injuries, which has affected every aspect of the game. However, they have not played well, especially when batting with runners in scoring position.

Undoubtedly, San Francisco will miss Vogelsong, but if the other starters begin performing up to their potential and their defense improves, the Giants will hold onto the lead in the NL West.