Article in the Herald hinted said he might have been pretty far down on the depth chart based on the reps he got in spring ball. He then got hurt and missed the last part of camp.
Per Tom Miller's Article -
"Based on when Martens' snaps came during the spring practices, though, it appeared he initially was in a deep group of safeties hoping to break into the two-deep....................
During spring ball, UND started Cole Davis and Ethan Ball at safety, with the next round of reps given to Sutton, Martin, Erkman and Martens."