The Illini have turned the ball over eight times in the last three games. They were able to lose the turnover battle against Northwestern and Western Michigan and escape with wins. They won't be as fortunate against the better teams.
The turnovers against Northwestern couldn't have come at a worse time (if there's ever a good time). The first was a Nathan Scheelhaase interception in the endzone. After a long drive, the Illini stalled on a First and Goal from the Northwestern 4. On third down, Scheelhaase rolled left, and floated an easy pick up to Brian Peters.
The final one came as the Illini attempted to run out the clock and ice the game. The Illini took over at their own 36 with 3:04 left, winning by three. A few first downs, and the game would be over.
Instead, on the first play, Jason Ford was rocked, and he fumbled the ball. Northwestern took over, and scored five plays later. This led the Illini to have to go on a six play drive in 1:05 to take the lead back.
These are mental mistakes. You cannot fumble the ball when you are trying to seal the game, and you cannot throw interceptions in the endzone, which takes sure points off the board.
Additionally, two meltdowns have cost the Illini time. Against Western Michigan, tackle Jeff Allen was kicked out of the game near the end of the first half for getting in a scuffle (although replays showed nothing conclusive). After review from the Big Ten offices, he was ruled eligible for the game against Northwestern.
Then, against Northwestern, linebacker Jonathan Brown delivered a blatant knee to a Northwestern player's groin. He was flagged for the act, but was somehow not ejected from the game. Illinois has suspended Brown for the game against Indiana.
These two actions belong in the same vein. Whether it is turning the ball over when you absolutely cannot turn it over, or losing your cool and kneeing another player in the groin, you have to keep your cool and stay mentally strong.