In September, Digger Phelps came up with his slogan for 1981-82: "The Rat Pack Is Back." In October, the Notre Dame basketball coach looked at his young team in practice and said hopefully, "We might steal 20."

It is now January and there is snow on the ground in South Bend. Beneath it lie his dreams that this would be a happy season. The Irish are 2-7. They have been embarrassed on national television by UCLA. They were beaten by Murray State (without its best player), Northern Illinois and one of La Salle's weakest teams in years.

Tonight Phelps may be in for a very long night against second-ranked Virginia (11-0), whom the Irish play at Capital Centre at 9. About 3,000 tickets still were available last night.

Part of the Irish problem is simple: the Cavaliers, led by 7-foot-4 Ralph Sampson, are quite good, a team likely to beat Notre Dame badly unless Phelps can control the pace as he did in taking Kentucky into overtime in a 34-28 loss 10 days ago.

That isn't all. Virginia is looking for revenge. Sampson undoubtedly remembers vividly the pounding he took last February in the 57-56 upset by the Irish, a game that ended Virginia's 28-game winning streak and knocked the Cavaliers out of the No. 1 ranking in the polls.

Interestingly, there is some speculation that Virginia, which plays at No. 1 North Carolina Saturday, might be looking past the Irish. Unlikely, says Cavalier Coach Terry Holland.

"I can see where people might think that, with us being ranked No. 2 and North Carolina No. 1," Holland said. "Our basketball program has come a long way, but not so far that we can look past Notre Dame to someone else down the road."

Even worse for Notre Dame, the Cavaliers have built their record with Sampson as only a little more than a role player. The junior center, who sat out a couple of games with a broken finger, has played on cruise control since his return. He is averaging 15 points and 11 rebounds a game and has tried to get the ball to his younger teammates.

The best of Holland's young players is sophomore Othell Wilson, the 6-foot guard from Gar-Field High School. He is averaging 15 points a game and keying a defense that picks up opponents much farther out than it did last year's team, another factor that probably will work against Notre Dame.

Two freshmen, Jim Miller and starter Tim Mullen, also have played substantive roles early, as has junior Craig Robinson.

Notre Dame has an All-America in point guard John Paxson, who averages 19 points a game. But outside of Paxson, the Irish are struggling. If he is healthy, 6-10 center Tim Andree is no match for Sampson; with the assortment of back and leg injuries that have bothered Andree, he will be in serious trouble.