There's so many leagues, it's hard to find many of them, but here's a start:
Infielder's Connor Callery and Connor McMann and outfielders Devon Garcia and Ryan Sargent are staying in Athens with the Southern Ohio Cooperheads. I didn't see any Ohio players on any other Great Lakes Summer Collegiate League roster. There's a lot of D-II and D-III players in the league, so hopefully the other guys are in leagues that are a bit more challenging. I'll try to search for a few others later.

Ohio Summer Assignments:

Great Lakes League: http://www.greatlakesleague.org/view/greatlakesleague

Conner Callery: Southern Ohio Copperheads
Devon Garcia: Southern Ohio Copperheads
Ryan Sargeant: Southern Ohio Copperheads
Conner McMann: Southern Ohio Copperheads

Prospect League: http://www.prospectleague.com/view/prospectleague

Micheal Klein: Terra Haute Rex
Jake Roehn: Springfield Sliders
Josh Peterson: Springfield Sliders
Anthony Morsla: Lafayette Aviators

Mink League: http://www.minkleaguebaseball.com /

Logan Jacik: St Joes Mustangs

Coastal Plains League: http://www.coastalplain.com /#

Tom Colletti: Florence Redwolves

Northwoods League: http://northwoodsleague.com /

Rudy Rott: Eu Claire Express
Kenny Ogg: Eu Claire Express
Gerry Salisbury: Rockford Rivets
Nick Kamrada: Rockford Rivets

Rocky Mountain Collegiate Baseball League: http://www.rmblcolorado.com

Spencer Ibarra: Boulder Collegians

Valley Baseball League: http://www.valleyleaguebaseball.com/view/valleyleaguebase...

Tony Giannini: CHARLOTTESVILLE TOM SOX

Is it just me or has the quality of players in the Great Lakes League declined over the years?

I may be mistaken, but that's what the League was for years.