With these 2010 Pirates, upon the slightest sign of something positive, there inevitably follows the crash and burn.

When Pedro Alvarez hit that 10th-inning home run in early August, maybe the most uplifting moment in PNC Park's dubious history, they lost 12 of the next 13.

When management signed three elite amateur pitchers two weeks later to a franchise-record investment, team officials spent the next few days reacting to a national leak of ownership's profit margins.

And now, when the team might have put together its most thorough back-to-back victories all summer, with a chance to sweep a contending nemesis ... ka-boom!

Atlanta 9, Pirates 3.

Zach Duke lasted just an inning-plus Wednesday night, allowing eight of 11 batters to reach and giving up four runs. So much for the fine starts by Brian Burres and James McDonald in taking the first two from the Braves.

The defense dropped the ball, booted it, and threw it away, drawing merciless boos from the 13,113 on hand. So much for those sharp fundamentals.

The offense ... well, one gets the idea.

Duke, now 7-13 with a 5.47 ERA, is beginning to make a case that he is the worst regular-turn starting pitcher in all of Major League Baseball: His losses are tied for fifth-most among all pitchers with 120 or more innings, his ERA is second-highest, and his .320 opponents' batting average is the highest.

All of that might be pointing to Duke's offseason exit after five-plus years in the rotation.

Duke will be eligible for salary arbitration a third and final time this winter, and indications are powerful that management will not tender such an offer, thus casting him into free agency. He currently is making $4.3 million and, because arbitration tends to give raises based largely on innings, he surely would make more through that process.

One possibility is that management would approach Duke about staying at a lower guaranteed figure, but even that is not certain.

Atlanta started out dinking Duke, and those soon turned to line drives, including Brian McCann's RBI single and Alex Gonzalez's two-run double in the first.

The second was worse, Duke giving up a cannon-shot double by mound opponent Derek Lowe, then a single and walk before manager John Russell took the ball, without saying a word.

In general, the Pirates' starters now have lasted three or fewer innings an incredible 12 times this season.

Daniel McCutchen relieved and fared no better, charged with four runs in 1 1/3 innings. One of those was unearned, but that was his fault, too: Lowe tried to put down a bunt, and McCutchen went for the lead runner at third and flung the ball into left field. A run scored, and it was 5-0.

Russell would use a total of eight pitchers, matching the Pirates' record for a nine-inning game. Just in case anyone was wondering why management promoted enough September callups for an 18-man staff.

The Pirates have not won three in a row since June 30-July 2, and they have not swept Atlanta in a three-game series since 1994.

One of the few bucking the crash-and-burn trend: Neil Walker's hitting streak was extended to 15 by a first-inning single up the middle. It is the longest by a Pittsburgh rookie since Rennie Stennett's 18 in 1971. Walker is 25 for 65 during the streak, with five home runs and 16 RBIs.

The only other highlights came for newcomers in the ninth: Pedro Ciriaco's RBI double was his first major-league at-bat, and it followed a double by Alvarez, who was 3 for 4. Later, Alex Presley sprinted out an infield single for his first major-league hit.

The franchise's worst season in a half-century saw the record fall to 47-92, eight losses shy of 100.

Colin Dunlap's blog on the Pirates is featured exclusively on PG+, a members-only web site from the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.