Luke Fickell has his work cut out for him during this transfer portal cycle. He needs to find 30+ players, with starters at most positions. However, most of that replacement is coming because of graduation rather than transfers. Wisconsin has 31 seniors who have exhausted their eligibility, and only about 17 (as of this writing) transfers are leaving.
That's a lot to replace; however, some programs have it far worse, simply in the transfers out category. Iowa State has close to 50 players transferring out. Oklahoma State is not far behind with 45 and counting.