Bill O'Brien was seen as a complete departure from the former Penn State coaching staff and family when he was hired, and as a result, he wasn't received with the warmest of welcomes. but he seems intent on keeping at least part of the preexisting staff in place in the hopes of at least keeping some continuity and familiarity from the previous regimes. According to Bob Flounders of the Patriot News, O'Brien will keep linebackers coach Ron Vanderlinden on the staff, although it is not immediately clear what position he will hold.
It's still not certain if Vanderlinden will remain PSU's linebackers coach but it does seem likely. The only other possibility would be a promotion to defensive coordinator but I'm hearing O'Brien might be considering other coaches for the DC spot.