Mayor R.T. Rybak's post-City Hall plans remain a mystery, but he's now made at least one long-term commitment in Minnesota.

Gov. Mark Dayton announced Tuesday that he had appointed Rybak to a four-year term on the new board overseeing Mayo Clinic's massive expansion in Rochester.

It's the first revelation of what Rybak might be doing after he steps down at the end of the year, although the extent of his duties on the board is not clear.

Rybak will be joined by his former chief of staff, Tina Flint Smith, who now holds the same position in the governor's office. Other appointments include former Wells Fargo Minnesota CEO James Campbell and Rani Engineering President Susan Rani.

Campbell and Rani have experience in health care and engineering, respectively. Rybak, meanwhile, is cited in a news release as understanding "how to create successful partnerships between the public and private sectors."

The board will oversee operation of what's being called the Destination Medical Center Corporation and approving their development plan. The state has committed $455 million to the project over about 20 years.