Just as the Seattle Art Museum enters a crucial phase of its expansion plans, Lisa Corrin — the woman who held the reins for the museum's exhibitions and artistic programming — has resigned.

Corrin, who began as deputy director for art and curator of modern and contemporary art four years ago, plans to leave SAM in the fall. She has accepted the position of director of Williams College Museum of Art in Williamstown, Mass.

"[The job offer] came up suddenly and unexpectedly," said Mimi Gates, director of SAM. " It's a great opportunity for her to assume the position of director. It's a step up."

SAM also is losing its associate curator of Chinese art, Hsueh-man Shen. In Seattle for just a year and a half, she is leaving for family reasons. Gates says a search for Shen's replacement is under way.

The timing is not auspicious for SAM, which needs to demonstrate a strong artistic vision and direction as it moves ahead with plans for two new venues. Still $55 million away from its capital campaign goal of $180 million, the museum is entering the final stretch before its scheduled opening of the new Olympic Sculpture Park on the Seattle waterfront in June 2006.

In January the downtown museum will close for expansion and SAM's main exhibitions will relocate to the Seattle Asian Art Museum in Volunteer Park. The downtown museum is slated to reopen in spring 2007 after expanding into a new Washington Mutual complex being built next to the existing museum.

Corrin made a big splash early on when she brought Korean artist Do-Ho Suh to Seattle for a two-part exhibit at the downtown museum and the Seattle Asian Art Museum in Volunteer Park. She added gutsy contemporary art to the sometimes staid and scholarly exhibition lineup at SAM's Asian art branch.

Yet, with multiple responsibilities for two major expansions as well as the day-to-day job of organizing exhibitions and encouraging patronage and gifts, Corrin hasn't always been able to keep the excitement of her early curatorial projects going. "Baja to Vancouver," a 2003 show of contemporary West Coast art she co-curated, was not a big hit for SAM.

Corrin says for someone climbing the ladder of museum administration, Williams College is an irresistible choice. It's been a proving ground for stars such as Michael Goven of the Dia Foundation, Thomas Krens of the Guggenheim and the late Kurt Varnedoe of MoMA.

"Most people would say it's a plum job," Corrin said. "If it had been for anything less, there is no way I would have left Seattle."

Sheila Farr: sfarr@seattletimes.com