"Because," Sabean said, "without being harsh, this group just isn't getting it done."
San Francisco entered Tuesday ranked 14th in the NL in scoring.
Sabean will keep trying to bolster the offense and indicated that he hasn't ruled out adding players who are potential free agents after this season, who formerly were on his forbidden list. But Sabean noted that the market for catchers and shortstops, positions where the Giants could use offensive improvement, is "almost nonexistent." He added that the overall supply of offensive "difference makers" is scarce.
Bringing aboard Keppinger, Sabean said, "kind of takes a little bit of the pressure off. But we'll still be on the phone to expand or lengthen this lineup any way we can because we think we need the help."
The Giants also recalled first baseman-outfielder Brandon Belt, their top position-player prospect, from Triple-A Fresno. But Belt's promotion resulted mainly from first baseman Aubrey Huff's sore lower back and did not reflect an offensive overhaul, combined with Keppinger's impending arrival. Bochy explained that his desire to keep Pablo Sandoval at third base instead of moving him to first to replace Huff required Belt's return.
Such thinking on the fly influenced the Keppinger trade. Sabean said that he had discussed Keppinger with Houston general manager Ed Wade but balked at including a second player in the swap. Sabean said he then shifted his focus to a "bigger" deal. But when shortstop Miguel Tejada strained his lower abdomen in Monday's third inning, Sabean knew the Giants needed another middle infielder and contacted the Astros about Keppinger.
"We revisited it this morning and put in the second name," Sabean said.
The presence of second baseman Bill Hall and Freddy Sanchez on the disabled list also spurred the Giants to action. They've been aware that they can't pin their hopes on the return of Sanchez, who's mending a dislocated right shoulder.
"You have to cover yourself," Bochy said.
So San Francisco obtained a player who's similar to Sanchez. Keppinger, 31, hit .307 with four home runs and 20 RBIs in 43 games for Houston after recovering from a foot injury that sidelined him until May 27. A quintessential contact hitter, Keppinger led the NL in at-bats-per-strikeout ratio in 2008 (19.1) and last year (14.3). He has played for the Mets, Royals and Reds besides the Astros.
"They have different skill sets, but the type of baseball they play -- they're gritty, they're grinding," said right-hander Sergio Romo, comparing Keppinger to Sanchez. "His approach to the game kind of fits us. He plays like he has nothing to lose. He's loose and confident. I think he's just another personality to add to the diversity of what makes this team."
The Giants are believed to be responsible for the remainder of Keppinger's $2.3 million salary.
Sosa, formerly a highly rated prospect who has weathered injuries and inconsistency through eight seasons in the Giants organization, was 5-2 with a 2.68 ERA in eight appearances (six starts) for Double-A Richmond and 3-1, 10.41 in 17 outings at Fresno. Stoffel, a non-roster invitee to Spring Training this year, was 1-2 with a 3.98 ERA in 32 relief appearances at Richmond.