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.
The Nittany Lions clinched a spot in the tournament after defeating George Mason 3-1 in the EIVA Championship Saturday night.
"I find it hard to believe any team is going to lose with that kind of service game."