Strib, in its own reporting and not carrying a press feed, published, "Gov. Mark Dayton won't talk U.S. Senate pick; possible choice Tina Smith keeps '18 run on table - Lt. Gov. Tina Smith still appears likeliest candidate. By Erin Golden - Star Tribune, December 8, 2017 — 9:59pm."
If, as reported there Tina Smith declines a Sherman statement as a "placeholder" in wanting to keep options open, what about getting a placeholder Sherman statement from Martin, and sending him to DC?
Yes, his party administrative post would require finding a replacement, but it would be a DFL opportunity to move progressively, away from the "same old" that saw both houses of the Minnesota legislature going decidely Republican during Martin's tenure atop the DFL inner-party tent.
Playing on an old saying, two rights do not make a wrong -
Ken Martin for interim (placeholder) Senator!
Or not. But at least it is an option Dayton, in objective candor, should consider. Also, presumably Martin would give a Sherman statement. Otherwise, he'd be Tina redux; with similar minuses and possible pluses.
Ken Martin's Wikipedia page link.