While control has always been an issue for Sanchez, this year he's fallen to a career worst 5.9 BB/9. In only 16 starts, Sanchez has walked six batters in four different appearances. He's also walked 5 batters in a game two times. While his ERA and strikeout numbers are perfectly fine, it's likely his walks will catch up with him. That less-than-sterling 1.43 WHIP should eventually cause the ERA to surge. His ability to avoid bats is tremendous (.204 BAA in 2010; .212 BAA so far this year), but if he keeps issuing free passes the Giants could be in trouble.
Of course, the Giants had to make room for Sanchez's return and Barry Zito will be the one making it. The Giants placed Zito on the DL for the second time in three months. (For the first decade of his career Zito had stayed injury-free.) In his return to the Giants rotation Zito dazzled -- posting three straight victories in which he allowed only 3 earned runs in 21 innings pitched. Over that stretch he allowed only 13 hits and issued just 4 walks. That said, Zito followed up his string of gems with three straight stinkers -- allowing 19 runs in 15 innings, with most of the damage coming off 6 home runs allowed.
What the 2011 Giants have lacked so far is a reliable fifth starter. While both Zito and Sanchez have shown flashes of dominance, they've also shown stretches of mediocrity and ineffectiveness as well. It's now Sanchez's turn to turn his season around by limiting the walks and dialing up the 2010 version of himself. With the Diamondbacks close behind in the NL West, the Giants can't afford unreliability at the back end of the rotation.