Some of these are going to change, but here's what we know thus far, as well as history behind those numbers.
The San Francisco 49ers hosted their rookie minicamp this past week, welcoming draft picks, undrafted free agent signings, and tryout candidates. The team handed out jersey numbers to all the players, and Matt Barrows jotted down 15 of the numbers. I have posted those below, along with the history of each number (via Pro Football Reference). 23 was assigned to two players as the team remains short of numbers due to 12 retired jerseys.