Source: Pittsburgh Panthers star WR Jordan Addison enters football transfer portal

The best of Pitt's standout WR Jordan Addison (2:28)

Check out the highlights from standout wide receiver Jordan Addison as he transfers to USC. (2:28)

The most riveting drama of college football's offseason took another twist Tuesday. Pittsburgh star wide receiver Jordan Addison officially appeared in the NCAA transfer portal Tuesday afternoon, a source told ESPN.

He had filed his paperwork to Pittsburgh saying that he intends to explore a transfer, which happened before the May 1 deadline and resulted in him appearing in the portal just after 3 p.m. ET on Tuesday.

Addison is one of the top returning players in college football, as he earned All-America honors last season and won the Biletnikoff Award for the top receiver in the sport. There likely will be a frenzy of interest for his services, as there are few more established players in the country.

A person close to Addison said Tuesday that the expectation remains that Addison will run a formal process after his name appears in the portal. He has yet to make up his mind on a destination, and there's no expectation of an imminent decision, according to the person.

"A return to Pittsburgh remains a very viable option," the person said Tuesday.

The expectation remains that this will not be a name, image and likeness (NIL) bidding war but rather a way to situate Addison best for the NFL. Seemingly, every powerhouse in the country will be a suitor.

Addison's transfer has become a source of consternation between the programs at Pittsburgh and USC, as a source told ESPN on Friday that Pitt coach Pat Narduzzi called USC coach Lincoln Riley multiple times to express his displeasure over Addison's potential transfer. Pitt officials suspect that tampering might have occurred.

The deadline to enter the NCAA transfer portal without requiring a waiver to play in 2022 was Sunday. Pitt compliance officials had two business days to put Addison's name in the portal, with Tuesday the last day it could have appeared.

Addison's potential transfer has emerged as a divisive and important issue looming over college football. It's a fascinating scenario in theory -- one of the most established players in the country could test his value on the open market. Addison caught 100 passes for 1,593 yards last season and had 17 touchdown grabs. He finished No. 5 in the FBS with 143 targets.

Pitt will have a new receivers coach (Tiquan Underwood), offensive coordinator (Frank Cignetti Jr.) and quarterback in 2022. Quarterback Kenny Pickett was the No. 20 pick by the Pittsburgh Steelers last week in the NFL draft.

As college football cycles through the sport's first full year of NIL rules, there's a sense that the potential transfer of one of the sport's most established players could cause enough ripples that the powers that be might consider an adjustment to the nascent rules.

It's unknown whether there has been any tampering by USC or other schools, but the specter of it, and the animosity from Pitt, has turned Addison's situation into a national talking point on how the rules should be structured in the new era.

Now that Addison has beaten the May 1 deadline to enter the portal, there's no urgency for him to make an immediate decision. Wherever he goes, he's likely to enroll in summer school, and those dates vary around the country.