SOUTH BEND, Ind. (AP) -- Notre Dame is still missing graduated linebacker Manti Te'o a quarter of the way through this season.
Without the charismatic leader who made those around him better, the once dominating Fighting Irish defense is meandering even with eight returning starters. The defense has given up one fewer point through three games (71) than it did through eight games (72) last season. The Irish defense, which allowed only nine offensive touchdowns all last regular season, already has given up eight this year.
''Our guys were like hunting dogs last year. In other words, when it was time to go, we knew what to expect,'' coach Brian Kelly said. ''We're not there yet, but I'm getting a better feel for our football team each and every week. I'd like to be there right now, but the problem is our first four weeks don't allow us time to grow up.''
While the 22nd-ranked Irish (2-1) opened the season against Temple and then split games with Michigan and Purdue, the Spartans (3-0) opened the season with wins against Western Michigan, South Florida and Youngstown State. Michigan State coach Mark Dantonio said he expects to learn more about his team Saturday.
''You are going to find out how they handle adversity, how they play away, look for matchups here, how do they play in crunch time in a close game, which we really haven't had that yet,'' he said.
The Spartans this season have looked more like the Irish of last season than Notre Dame has, depending on the nation's No. 1 defense to win games. Defensive end Shilique Calhoun has led the charge with three touchdowns on a pair of fumble recoveries and an interception return as the defense scored four of the Spartans' first six touchdowns.
But Irish linebacker Prince Shembo believes the Irish defense is still capable of playing like it did last season.
''It's just lack of execution. We've just got to work at our assignments and get better at it,'' he said.
The Irish defensive line, which has not been as productive as last season, could be further hampered by an ankle sprain defensive end Sheldon Day sustained against Purdue. Day practice Thursday after missing the first two days of practice this week, but Kelly said he will be a game-time decision.
Kelly admits the Irish are still searching for their identity, but believes quarterback Tommy Rees showed leadership against Purdue in the second half that should help with that. With three players sharing the two inside linebacker spots and a first-time starter at safety in Austin Collinsworth, Kelly is looking for people to help fill the leadership void left by the departures of Te'o and Zeke Motta.
''Those are two positions we're still in flux a little bit with,'' Kelly said. ''We've got leaders; we just haven't got that position nailed down yet. I think once we do, we'll have the leadership we need.''
Here are five things to watch in the Michigan State-Notre Dame game on Saturday:
WHAT'S COOKING: Michigan State quarterback Connor Cook will make his first start against a BCS-level opponent after winning the job by throwing for four touchdowns in the first half in a 55-17 victory against Youngstown State last week. He'll be going against a Notre Dame defense that is 89th in the country in pass defense, 56th in total defense and has struggled against mobile quarterbacks.
GROUND GAME: The Irish are 24-4 in four seasons under Kelly when outrushing opponents, while the Spartans are 43-10 in seven seasons under Dantonio with the rushing advantage. So far this season, Michigan State, behind the rushing of Jeremy Langford and Nick Hill, has been the better rushing team. The Spartans are averaging 210 yards a game while the Irish, who have three running backs sharing the load, are averaging just 125 yards.
300 CLUB: Tommy Rees is just the second Irish quarterback to pass for 300 yards in three straight games to open a season and could become the first to do so in the first four. He had accomplished the feat only two times before this season, losing both games. The Michigan State defense has given up just 380 passing yards total in three games this season, including a high of 193 yards against Western Michigan.
THRILLING FINISHES: Nine of the last 13 games in the series have been decided by a touchdown or less and four of the last eight by a field goal. Those exciting finishes include Michigan State beating Notre Dame 34-31 in 2010 on a fake field goal in overtime when Dantonio was hospitalized afterward because of a mild heart attack and Notre Dame winning 33-30 a year earlier when safety Kyle McCarthy intercepted a pass from Kirk Cousins at the 4-yard line with 57 seconds left.
ANOTHER RIVALRY: For Notre Dame this is the third straight week of playing a team known as a rival, while for Michigan State it is their first big game of the season. The Spartans' 28 victories against the Irish are the second most of all opponents, trailing only USC with 35. The teams don't meet the next two seasons as they take a periodic pause in the series, but the future of the rivalry is in jeopardy. With Notre Dame promising to play five Atlantic Coast Conference teams a year, Notre Dame has to make decisions on whether to keep teams like Michigan State and Purdue on its schedule.