He made the call himself to go for it, and just barely pulled it off.
Posey also produced a second straight three-hit game, Madison Bumgarner backed up his nice, new contract with a second consecutive win, and the San Francisco Giants beat the Philadelphia Phillies 4-2 on Tuesday night.
Posey's successful steal allowed the Giants to check off yet another milestone in his return after last year's season-ending left leg and ankle injury from a collision at the plate with the Marlins' Scott Cousins.
"I think he surprised all of us," manager Bruce Bochy said. "He knows if they forget about him, he can go. I think he thought he was moving faster than he was on that stolen base. He made a nice slide to avoid the tag."
It was a close play at third in the fifth in which he appeared to get his left hand under Placido Polanco's glove and touch the bag before the tag was placed. Polanco argued and manager Charlie Manuel came out as well but replays showed Posey safe.
"I did feel like I got in there," Posey said. "I didn't really walk into it as much as I wanted to."
Posey had back-to-back three-hit games for the first time since May 29-30, 2010, against Arizona during his NL Rookie of the Year season. Those were his first two games after getting promoted to the majors.
While Posey's hitting is a jolt for the lineup, his teammates like seeing him running well on the bases, too.
"Awesome," Angel Pagan said.
The finale Wednesday night for an expected sellout at AT&T Park is another highly anticipated pitching matchup after Monday's Tim Lincecum vs. Roy Halladay: San Francisco's Matt Cain and Phillies ace Cliff Lee.
Melky Cabrera hit an RBI triple, Nate Schierholtz had three hits and drove in a run, and Pablo Sandoval doubled leading off the fifth to extend his hitting streak to start the season to 11 games.
Bumgarner (2-1), pitching a day after receiving a new $35.56 million, six-year contract, outdid Joe Blanton (1-2) and gave San Francisco a shot at a third straight series victory.
Bumgarner's deal includes a $1 million signing bonus, a $560,000 salary for this year, $750,000 for 2013, $3.75 million in '14, $6.75 million in '15, $9.75 million in '16 and $11.5 million in '17. He has club options of $12 million for 2018-19 with $1.5 million buyouts. The 2018 option would become guaranteed if he pitched 200 innings in 2017 or 400 innings in 2016-17 combined and he doesn't finish the '17 season on disabled list with either a left shoulder or left elbow injury.
Hunter Pence hit a solo home run into the left-field bleachers leading off the fourth for the Phillies.
Bumgarner allowed seven hits and two runs in six-plus innings, struck out two and walked one. Then, the Giants' bullpen did the rest, - a nice boost considering closer Brian Wilson is expected to undergo elbow ligament surgery and miss the season. Clay Hensley and Sergio Romo each pitched a scoreless inning, then Santiago Casilla finished for his first save in his first chance since Wilson went down last week.
"Our staff is well armed to pitch in whatever situation when called upon," Romo said. "We're not really fazed by it."
Pagan led off the first with a single, then Cabrera tripled to end an 0-for-12 stretch and the ball stopped under the bullpen bench in the deepest corner of right field. Sandoval's RBI groundout brought home Cabrera for a 2-0 lead. Posey followed with a bloop single to center. Pagan hit his third triple of the year in the second.
Brandon Crawford was the only San Francisco position player without a hit.
The typically sure-handed Giants shortstop also committed a fielding error to start the game, allowing Shane Victorino to get aboard. Then, Victorino advanced on another error - a low throw that Crawford couldn't contain for an error on Bumgarner.
But Jimmy Rollins grounded into a double play and Bumgarner retired Pence on a high popup to first baseman Aubrey Huff just behind the mound to escape unscathed. Carlos Ruiz had a sacrifice fly in the sixth for Philadelphia's second run.
"We couldn't get it done. The first inning kind of hurt us. We couldn't deliver," Manuel said.
Notes: Wilson on Wednesday is set to be examined by Dr. James Andrews, who performed his first Tommy John surgery while he was in college at LSU in 2003. ... Injured Giants 2B Freddy Sanchez, still working back after offseason right shoulder surgery, is set to resume throwing Wednesday after he complained of soreness from playing in an extended spring training game Monday in Arizona. ... Crawford has five errors.