EUGENE — Mario Cristobal’s national signing day press conference was already well underway when Oregon’s compliance office gave the coach permission to talk about his prize prospect.

Penei Sewell was worth the wait.

The Ducks beat Alabama and USC on Wednesday for the 6-foot-5, 350-pound offensive lineman, who added some weighty four-star power to the 22-man recruiting class.

“It’s a great example of the types of battles that Oregon is capable of winning,” Cristobal said. “He’s an ultimate difference maker. … Penei kind of caused an explosion in the room when it was official.”

Despite the ill-timed departure of Willie Taggart as head coach and the loss in the Las Vegas Bowl late in the recruiting cycle, Cristobal and his staff were able to secure a class ranked 15th nationally by Rivals and 16th by 247Sports.

Oregon added eight prospects on Wednesday after landing 15 players during the early signing period in December.

The program also announced that D.J. Johnson — one of the highest-ranked defensive line prospects in 2017 — has officially transferred to Oregon from Miami.

“I do think it’s important to note that if D.J. was actually counted as part of this class, OK, there are very few guys like him, where does this class stand?” Cristobal said. “This is a really, really big deal for us. … Those guys are hard to find.”

Johnson probably will have to redshirt in 2018, per the NCAA transfer rules, but several recruits will have an opportunity to contribute immediately.

The Ducks added four pass-catchers from California — wide receivers Isaah Crocker, Jalen Hall and J.J. Tucker, and tight end Spencer Hall — who will all compete for playing time as true freshmen.

Several high-profile receivers decommitted from Oregon after Taggart departed for Florida State, including two players who also took their talents to Tallahassee (Warren Thompson and Tre’Shaun Harrison).

“We probably fell a little bit short at the wide receiver position in terms of numbers. We wanted another one or two,” Cristobal said. “We were able to get three and had the tight end Spencer Webb, who played a lot of wide receiver all year long.

“So you’ve got four guys that can make a difference in the passing game. That was of utmost importance.”

Cristobal plans to continue coaching the offensive line and welcomed Justin Johnson, whom he dubbed the “human eclipse,” to the unit when the 6-foot-7, 342-pound prospect from Philadelphia sent his paperwork in at 4 a.m. Wednesday.

In addition to Sewell and Johnson, Oregon signed offensive linemen Dawson Jaramillio (6-5, 395), Steven Jones (6-6, 340) and Christopher Randazzo (6-7, 330) in December.

“The amount of size and power that we added to the offensive line was critical,” Cristobal said.

Linebacker Andrew Johnson, of Tifton, Georgia, signed on Wednesday, joining a position group that added four-star recruits M.J. Cunningham and Adrian Jackson in December.

Oregon’s class includes players from 11 different states with six defensive backs, four offensive linemen, three linebackers, three wide receivers, two defensive linemen, two running backs, a quarterback, a tight end and a long snapper.

Quarterback Tyler Shough is among the members of the 2018 class already enrolled at UO early to participate in the strength and conditioning program and spring practice.