The Sixth Circuit, which covers Kentucky, Michigan, Ohio, and Tennessee, has 16 active judgeships. They’re all filled, but Judge Jane Branstetter Stranch has opted to take senior status effective upon the confirmation of her successor.
The court has 9 appointees of Republican presidents (3 GW Bush, 6 Trump) and 7 appointees of Democratic presidents (2 Clinton, 1 Obama, 4 Biden), including Stranch.
Of the appointees of Republican presidents, Richard Griffin is eligible to take senior status, and Jeffrey Sutton (whose tenure as chief judge runs until 2028) will become so when he turns 65 next October.
On the Democratic side, in addition to Stranch, Eric Clay and Karen Nelson Moore, both of whom are (or perhaps very soon will be) 76, are senior-eligible.
I would guess that Griffin is the judge most likely to join Stranch in stepping down from active service.
The Sixth Circuit is well positioned to increase its current 9-to-7 margin of appointees of Republican presidents to 10 to 6.