There's a huge class difference here that's not fully incorporated into the line. 
Winthrop had opened with 16 consecutive victories until losing, 57-55, as 12 1/2-point home favorites against UNC-Asheville in its last game. That was two weeks ago. The Eagles haven't played since. So they are more than ready to put that disturbing upset loss behind them.
The Eagles are the class of the Big South Conference. Radford is a surprising 13-7, in second-place behind Winthrop in the league standings despite losing all of its top scorers from last season. None of Radford's players average double figures in scoring.  Winthrop ranks 22nd in the nation in scoring at 81.3 points and has the conference's likely MVP in Chandler Vaudrin. 
Winthrop has proven itself in this type of situation going 13-4 ATS versus above .500 opponents and covering 17 of its past 24 road contests.