Howabout Randy Ruiz?
(preseason primer:
http://mopupduty.com/index.php/randy-ruiz-profile/)
He's not a kid, 28 years old or so, and would have the same role as Millar but if he exceeds expectations (read: keeps up his current pace) then he might keep the job for next year.
If he flames out, no loss. Start fresh next year (or in September).
This half-rebuild half-patchjob teambuilding isn't working.