by Patricia Sellers

Sallie Krawcheck has landed back at another troubled bank giant. Citigroup's (C) onetime CFO, who later headed global wealth management there and clashed with Citi CEO Vikram Pandit, has accepted a job at Bank of America (BAC).

Her new position—leading BofA's global wealth and investment management business—comes as a surprise, since she has been off the radar since Pandit demoted her last September and she left Citi soon after. Last Wednesday, Krawcheck and I had lunch, and she shared, off the record, several big opportunities that she had turned down--because they didn't "hit the bulls-eye," she told me. And particularly in this treacherous environment, "there's no use rushing," she added.

I got the sense that Krawcheck was poised to decide on something soon--though not this soon. And my bet was that she might start her own asset management company with backing from private equity investors.

So I was wrong about her plan, but I'm sure about this: By choosing BofA, Krawcheck is staking her career on a slow-going turnaround. BofA's stock has risen from a $3 low to $15, but it's down from $55 last fall after CEO Ken Lewis agreed, under pressure from the government, to rescue Merrill Lynch. That said, by taking the job at BofA, Krawcheck could be setting herself up for something bigger, which she could hardly achieve at her own firm. That is, a chance to be a Fortune 500 CEO.

Especially in light of the ongoing shakeup of BofA's board (bucking to pressure from the Obama Administration, the board is replacing its directors), the heat is on CEO Ken Lewis to hasten the turnaround or give up his position to a successor. Along with the news about Krawcheck's hiring came an announcement that one longtime succession candidate, consumer and small-business banking boss Liam McGee, is leaving the company.

McGee's departure leaves a couple of succession candidates. One is Brian Moynihan, who arrived at BofA with its 2004 Fleet acquisition and has recently headed the global corporate and investment banking unit, plus global wealth management. He's newly assigned to oversee BofA's mighty consumer bank, including its small business and credit card operations.

Another possible successor is Barbara DeSoer, a nose-to the-grindstone operator whom my Fortune colleague, Geoff Colvin, interviewed last November. DeSoer has earned high marks for integrating BofA's Countrywide Financial acquisition and cleaning up the big mortgage minefield. (Another BofA succession candidate who was on Fortune's Most Powerful Women list, chief risk officer Amy Brinkley, paid for those disastrous investments and was ousted in June.)

Following all this tumult, BofA has two newcomers to watch closely: corporate and investment banking chief Tom Montag, who came with last year's buyout of Merrill Lynch and was at Goldman Sachs (GS) before that. The other is Krawcheck. Given her youth--she'll be 45 in November--and her time off the grid, the onetime most powerful woman in banking won't have an easy time proving herself at battered BoA. Then again, Krawcheck's reputation as a champion of individual investors--"the last honest analyst" as Fortune once dubbed her--is in line with the zeitgeist. And certainly in line with where BofA needs to go.

Here's Krawcheck in a conversation with Elliott Spitzer and Fortune's Allan Sloan, taped last Monday at CNNMoney's studios: