According to an industry source, Mychael Urban will soon return to KNBR 680.

Urban should resume the same role he held through the 2010 baseball season on weekends — hosting the San Francisco Giants’ pre-pregame show at the Public House, along with handling postgame duties immediately after Dave Flemming tells everyone “what’s on tap” — shortly after the All-Star Break, if not before. He’ll also see time as a fill-in host on weekdays, something he still did occasionally even after KNBR Program Director Lee Hammer released Urban from weekend duties before the 2011 season.

What led KNBR to bring Urban back into the fold? Here are a few possible reasons that stand out.

1. This may not have been Hammer’s decision.

Cumulus brought in Bill Bungeroth in March to oversee Cumulus’ San Francisco stations, which in effect made him Hammer’s new boss. One of Bungeroth’s primary goals upon arrival? Crush FM. Namely 95.7 FM, the upstart sports talk station that recently signed former KNBR personality Dan Dibley and wanted to add Urban, too. Cumulus noticed a level of complacency at KNBR in recent years — including alarmingly low ratings for Gary Radnich and Fitz and Brooks — and the suits made it clear: changes needed to be made. The last thing Bungeroth and Cumulus wanted was Urban, a guy who writes and does a significant amount of TV work, returning to the radio on a competing station.

2. Marty Lurie’s pitch count got a little too high.

Lurie, buoyed by unprecedented Giants success and to a certain extent a degree of novelty (Who else would talk until 11 pm on Sunday before playing recorded Bill Hayes interviews until the midnight replay?), took over all weekend duties after Urban’s deal wasn’t renewed.

For Hammer, it was a situation where a relatively inexpensive (read: free) host was earning kudos from listeners (and Ashkon), all while performing like talk radio’s version of an ultrarunner. So Hammer decided to take Lurie out of the bullpen and make him a full-time starter.

Lurie certainly has his fans, but Urban’s delivery, interviews and topics trend much younger. Once fans knew what to expect from Lurie, the prospect of listening to him all day long every Saturday and Sunday without Urban to liven up the proceedings didn’t lead to the ratings carryover Hammer hoped for.

3. Urban didn’t burn any bridges.

Sure, I’d love to be a media yakker (In a related plug: check out my recent interview with Tim Roye!), but the radio game isn’t for the faint of heart — or those with thin skin.

While Urban let it be known he wasn’t happy with Hammer’s decision, he not only refrained from ripping KNBR, he also made himself available. He filled in as a host on a few occasions, continued to do guest appearances with current KNBR hosts like Damon Bruce and Eric Byrnes, and kept his options open. Urban waited for his shot … and this week, according to my source, he took advantage.