Brian Kelly's second season as Notre Dame's coach got an early boost when leading receiver Michael Floyd decided against leaving for the NFL.

Now Kelly's putting the touches on his first full recruiting class. He already has five early enrollees on campus and will be sorting out his quarterback situation once spring football starts in a couple of months.

The goal remains the same following an 8-5 first season, including a win over Miami in the Sun Bowl, and that's to capture a national championship. Kelly said Friday that even with his high-octane spread offense, the Irish must play strong defense — like they did in winning their final four games — if they want to climb to the top.

In their final four games, the Irish played their best defense of the season and in two of those victories over Utah and Army, Notre Dame gave up only a field goal.

"If you want to win a national championship you can't do it like we did at Cincinnati or Central Michigan. You can't just try to outscore people because they are going to get you," Kelly said. "You don't get to that (national championship) game unless you play good defense."

Kelly also disclosed Friday that walk-on place-kicker David Ruffer, who is 23-for-24 in field goals during his career with his only miss coming in the Sun Bowl, will return for a fifth season and get a scholarship.

Ishaq Williams (linebacker), Aaron Lynch (defensive end), Brad Carrico (defensive end), Everett Golson (quarterback) and Kyle Brindza (kicker) were all on campus as early enrollees. The full recruiting class will be introduced on Feb. 2.

Kelly said recruiting nationally, as Notre Dame does, is a different endeavor.

"You have go into SEC country or Pac 10 or Big Ten and you are taking their kids. That's the way they are looking at it. It requires a tenacity and attention to detail," he said.

Where the mobile Golson fits will be an interesting dynamic in spring practice, when the Irish hope to have last year's starter, Dayne Crist, back following his second knee surgery in as many seasons. Tommy Rees, who stepped in when Crist was hurt during a game against Tulsa that the Irish lost, started the final four games. Notre Dame won all four, beating Utah, Army, Southern Cal and Miami.

Kelly said that he would scale the number of probable quarterbacks down to four, even though there will be a half-dozen on the roster. Andrew Hendrix will be in the mix to challenge Rees and Crist.

"I have formulated in my mind clear guidelines how we are going to move forward," Kelly said, declining to be specific because he had not talked yet with his quarterbacks.

"I'm pretty clear on styles we have and how to utilize those styles within our offense. Not everybody can run the style offense that I would want us to be running. We're going to utilize our quarterback to best help us win football games."

Kelly said he learned two things about Rees, who was an early enrollee a year ago. That he's tough and he's accurate. Whether he's still the starter remains to be seen.

Floyd caught two TD passes in the Sun Bowl from Rees, giving him a school-record 28 scoring receptions, and he said that either Crist or Rees could do the job.

The 6-foot-3, 227-pound Floyd enters his final year with the second-most receptions (171) and third-most receiving yards (2,539) in school history.

Several factors weighed on his decision to stay in school. Some projections had him as low as a third round pick, he wanted to come back and prove he is the best receiver in college football and improve his draft status next year, and he wanted to keep a promise to his mom that he would get his degree.

He said he also liked being a college student.

"It was just basically my own decision and what I felt would be better for my life," Floyd said.

The Irish did lose a star receiver to the NFL in tight end Kyle Rudolph, who played only six games last season because of a severe hamstring injury.

Kelly said three players had undergone surgery in the offseason — nose tackle Sean Cwynar (foot and back), safety Jamoris Slaughter (ankle spurs) and nose tackle Tyler Stockton (shoulder).