The San Francisco Chronicle’s John Shea grieves, while Punchy A.J. gloats.

In a lot of ways, the Giants are shaped the way they’re shaped because of Joe Mauer (above), the gifted Twins catcher who prompted a trade that Giants fans dearly regret.

Mauer’s presence in the Twins’ organization led to the November 2003 trade of catcher A.J. Pierzynski to the Giants, and the domino effect has amounted to a loss for the Giants, a win for the White Sox and a win-win-win for the Twins.

Pierzynski spent one tumultuous year in San Francisco, and the Twins’ pitching staff is well stocked, thanks largely to the three pitchers gift wrapped by the Giants.

“A.J. was an All-Star at the time, but we got some pretty good players out of that deal,” said Mauer, an All-Star in his third season. “It seems to have worked out for us.”

Uh, yeah.

Joe Nathan immediately succeeded as a closer and was an All-Star in 2004 and 2005. He could have made it a trifecta this year, based on his 5-0 record and 1.75 ERA, along with his 52 strikeouts and five walks in 36 innings. He converted 15 of 16 save chances.

Rookie left-hander Francisco Liriano, one of the baseball’s biggest stories of 2006, is 10-1 with a 1.83 ERA and allowed 87 base runners in his first 881/3 innings. He has 102 strikeouts.

No. 5 starter Boof Bonzer is 2-2 with a 5.30 ERA in seven starts and is expected to be back from the minors after the All-Star break.

“I couldn’t be any prouder with the way it worked out,” Pierzynski said. “It worked out great for both sides — it worked out great for me, and it worked out great for Minnesota.”

It didn’t exactly work out great for the Giants.

“Like I said,” said Pierzynski, cracking a smile, “I couldn’t be any happier with the way it came out.”