Four years ago in 2016, Sanders did win in Michigan in a close race over Hillary Clinton, but Clinton's easy victory in Mississippi gave her the edge that primary night.
In 2020, Michigan is the biggest prize in the six contests set for Tuesday, with 125 delegates at stake.
Also voting with Michigan will be, Washington State (89 delegates), Missouri (68), Mississippi (36), Idaho (20), and North Dakota (14).
On Thursday, the race further narrowed as Elizabeth Warren dropped out, joining Tom Steyer, Pete Buttigieg, and Amy Klobuchar, as the Democratic field has rapidly narrowed in less than a week.
Sanders supporters had hoped that Warren might endorse their candidate, but instead she will stay on the sidelines for now in the Biden-Sanders fight.
While Warren remains uncommitted, Klobuchar is throwing herself right back on the campaign trail for Biden, going to Michigan for a series of Biden events on Friday and Saturday.
Meanwhile, Michigan Democrats began to come off the bench on Thursday for Biden, continuing an absolutely unprecedented wave of party endorsements for the former Vice President.
"We need a president who will show up and fight for Michiganders, and Joe Biden has proven time and again that he has our back," said Michigan Gov. Gretchen Whitmer.
"Today, I filled out my absentee ballot for Joe Biden," said Rep. Elissa Slotkin (D-MI), a freshman Democrat in Congress from Michigan.
The quick reshuffling of the deck in the Democratic race was also showing a dramatic edge for Biden in Florida, which holds its primary on March 17 - and could provide a further boost for Biden over Sanders - as a new poll showed Biden leading Sanders by 49 points.
Florida has 219 delegates at stake on March 17. A win of that size for Biden would more than erase the 60-plus delegate advantage that Sanders currently has in California, where votes continue to be counted in Tuesday's primary.
352 delegates are up for grabs in six states on March 10.
577 delegates are at stake on March 17 from Florida, Illinois, Ohio, and Arizona.