After more than a year in stealth mode, Uber, which became synonymous with "gig economy," is launching a staffing business in Chicago on Friday to supply on-demand workers to other companies.

The new business, called Uber Works, has been in stealth mode in Chicago for more than a year. It’s the second business outside Uber’s original on-demand taxi service based in Chicago. Uber Freight, an on-demand trucking platform, is run from Chicago, where the company plans to add 2,000 jobs as it moves into the Old Post Office downtown.

Uber Works will be led by Andrey Liscovich. He declined to specify how many employees the unit will have but said, "We plan to grow rapidly."

Uber’s move into temporary staffing is not entirely surprising. At its core, Uber is a mobile app that allows workers to find jobs driving people from one place to another.

Temporary staffing is slightly different, because employers need workers for defined shifts. Uber will partner with staffing agencies, starting with TrueBlue, to handle the paperwork for employment screening, verification and payroll.

Meanwhile, Chicago has become a test bed of sorts for the gig economy. Shiftgig, which started as an online site for workers in the hospitality business, ultimately morphed into a contract-staffing agency that supplied temporary workers for industries as varied as retail and warehousing. The company ultimately sold off its staffing business to focus on tech. BlueCrew, a competitor acquired by IAC that moved to Chicago this year, employs its own workers. And Chicago-based food-ordering and delivery company Grubhub, which also has become a significant player in the gig economy, treats its drivers as independent contractors.

Uber appears to be deliberately avoiding becoming the official employer of the workers it provides by partnering with staffing agencies.

“We built the technology platform to solve the challenge for workers,” said spokesman Xavier Van Chau. He said the contract-staffing business is still largely analog.

As Uber searches for profitability, it’s looking for ways to wring more revenue out of its brand and technology platform. Uber, which already has 3.9 million drivers in its taxi business, also has 400,000 drivers in its freight operation. Uber Works will open the platform to workers outside transportation.

"We'll make (Uber Works) available to drivers," Liscovich said. "This will give us a more diverse workforce than our ride-share client base. It will open the platform up to people who want to earn money but who don't have cars."

Uber’s move into staffing comes at a tricky juncture for the gig economy. As more service workers find themselves struggling to obtain wage increases and benefits such as health insurance, there is a growing political backlash. California recently passed a law that would require companies such as Uber, Lyft and Grubhub treat gig workers as employees rather than contractors.

State Rep. Will Guzzardi says he’s considering similar legislation in Illinois.