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04/09/2013 9:23 PM ET

Sanchez again gets nod to catch Lincecum

SAN FRANCISCO -- Once again, backup Hector Sanchez caught right-hander Tim Lincecum instead of starter Buster Posey.

Once again, Giants manager Bruce Bochy insisted that no hidden agenda existed -- certainly nothing that would suggest, as he has maintained, that Lincecum and Posey simply don't mesh.

"I knew I would be answering this question," Bochy said before Tuesday's game. He pointed out that Posey needed to sit out either Monday or Tuesday, with a Wednesday afternoon series finale scheduled (meaning short rest). Because, Bochy added, Colorado will start a left-handed pitcher (Jeff Francis) on Wednesday, demanding Posey's presence in the lineup.

Bochy acknowledged that Sanchez, who committed a passed ball during his five-inning stint with Lincecum last Wednesday at Dodger Stadium, looked less than fully sharp in the only other game he has started.

"To be honest, Hector struggled at times, I think that's fair to say," Bochy said. "Timmy's not easy to catch sometimes. The ball moves so much and he will bounce some pitches."

Bochy didn't rule out assigning Sanchez to be Lincecum's personal catcher if they get in sync with each other.

In another lineup-related matter, Bochy said that second baseman Marco Scutaro, who has played every inning so far, probably will receive a rest in Thursday's opener of a four-game series against the Chicago Cubs at Wrigley Field. Bochy added that rookie Nick Noonan likely would replace Scutaro.

Affeldt adjusts to get right against lefties

SAN FRANCISCO -- The Giants value left-hander Jeremy Affeldt for being equally effective against left-handed and right-handed batters alike.

This was not always so.

Typically, most left-handed pitchers have a significant edge against lefty hitters. But during his first three seasons as a full-time reliever, Affeldt was markedly tougher against righties. They batted .211, .255 and .187 off him from 2007-09, respectively, compared to .250, .269 and .211 for lefties.

Affeldt had a simple explanation for this: He couldn't pitch inside to lefties, thus neutralizing any advantage he should have enjoyed.

"I couldn't throw a strike," Affeldt said Tuesday, one night after he pitched his third scoreless inning in as many outings. He recalled that he'd throw as hard as he could to left-handed batters, who came to expect fastballs from him. So they'd drive opposite-field hits to left. Affeldt had a curveball in his repertoire, but it traveled an extremely vertical path -- known in baseball parlance as "12 to 6," like a clock. Umpires rarely called it a strike and hitters seldom swung at it.

Affeldt adjusted by imparting more movement on his fastball and concerning himself less with velocity. He lowered his arm slot and started throwing his curve along more of a "10 to 4" path, enabling him to cover two planes of the strike zone.

In 2011, Affeldt devastated left-handed batters, holding them to a .144 average. Righties hit .248 off him. He reached consistency last year, as his opponents' batting averages against lefties (.236) and righties (.244) attest.

"I can go away, I can go in, I can go up, I can go down, I can throw curveballs and splits," Affeldt said. "I just have a lot more weapons than when I started. I'm more methodical about how I pitch."

Chris Haft is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.