Kerkvliet is set to return for his sixth and final year of NCAA eligibility.
Wylie didn't appear in the Blue-White Game last month and was absent during the last few media availability of spring practice.
Israel-Achumba joined safety King Mack, wide receiver Malik McClain, and running backs London Montgomery and David Kency Jr. in the portal.
Kency became one of five Nittany Lions to hit the portal Thursday.
John Kerr, Toby Ezeonu, Ryan Merk, and Owen Rose were all recognized.
Johnson joins Mike Gesicki, Brenton Strange, and Pat Freiermuth as former Penn State tight ends currently in the NFL.