SAN FRANCISCO -- Zack Wheeler, the Mets starter whom the Giants drafted sixth overall in 2009, taunted his former organization with what could have been on Wednesday afternoon, but San Francisco's most-pressing concern laid with its 2002 first-round pick.
For the first time in 254 career starts, Matt Cain failed to get through the first inning in a 7-2 loss to the Mets at AT&T Park. Cain, who has frequently been the Giants' stopper in recent seasons, had no command of the strike zone. He allowed three walks and two hits that led to three Mets runs before Wheeler even took the mound.
Cain did not last three innings in either of his two starts during San Francisco's 1-5 homestand, the worst since 2010. Manager Bruce Bochy said there is no health issue that has led to Cain's struggles or the quick hook -- Mike Kickham was warming up by the fourth batter and came in after Cain could not record the third out.
"I didn't want it to become a health issue," said Bochy, who added that he was worried about Cain's first-inning pitch count that reached 36. "He's fine. I had some concern there because he was a little off.
"I'll be honest. You want to win every game, but you don't want to risk someone to win a game. That's why I got him."
Cain's issues at AT&T Park have pervaded his 2013 campaign. He entered the game with the second-worst home ERA (5.50) of any National League starter, and that figure rose to 5.94 by the time his outing -- the shortest by a Giants pitcher since Sept. 24, 2011 -- had ended. He lasted just 2 1/3 innings last Friday when he allowed eight runs against the Dodgers.
According to FanGraphs, Cain is throwing fewer fastballs than ever before this season (47.2 percent of pitches), and when he does throw a heater, its average velocity is at a career-low 91.1 mph.
"I wasn't throwing strikes and [I was] falling behind in counts," Cain said. "And when I was throwing strikes, I was leaving the ball up."
San Francisco never threatened to eliminate the three-run deficit; no Giant reached scoring position until the Mets led 7-0 in the seventh. It was Wheeler's third win since debuting last month, but he might have saved his best performance for his former organization, as he went seven innings and allowed just three hits while striking out five.
"I was really looking forward to it," Wheeler said. "I think I told some of the guys earlier that I really wanted to do well. I was able to do that and it feels pretty good."
The Giants traded Wheeler to the Mets for slugger Carlos Beltran ahead of the 2011 non-waiver Trade Deadline. San Francisco missed the postseason that year, and Wheeler left the club pondering how fate might have played out differently had the Giants held onto him.
"He's got a good fastball, life to it," Bochy said. "He's got good stuff. We're not swinging the bats well right now and [opposing pitchers] are hard to read in some games, but he pitched well."
Wheeler, who didn't allow a hit through 3 2/3 innings, even contributed offensively. He doubled and recorded his first Major League RBI in the sixth and later scored.
"I just tried to come in there and keep it close," said Kickham, who was optioned to Triple-A Fresno following the game. "I did that the first few innings, but I got hurt on a pitch up [in the fifth] and allowed a couple runs the next inning."
The pitch Kickham referred to was a 1-0 changeup to Marlon Byrd, who gave the Giants' pitching staff fits in the series. In Tuesday's 10-6 win for the Mets, his grand slam off Jake Dunning marked just the sixth by an opponent in AT&T Park history.
The Giants head to San Diego for their final series before the All-Star break 10 games under .500 at 40-50. The club has lost 14 of 16, the worst stretch since 2005.
"You try to stay away from [thinking negatively], and think every day it's going to turn around," Bochy said. "We were hoping to come home and turn it around.
"This was an awful homestand."