Vollmert is the first General to win a weekly-award in 2021.
The Generals hold a league-best 9-3 record.
Brennan Fisher went 5-for-6 in the blowout win on Friday.
There were five lead-changes in Joliet's 14-12 win on Thursday.
Alex Rakas legged out an inside-the-park home run to seal the deal in the Generals 8-2 win.