Bye week to-do list: Northwestern

Northwestern's record is a perfect 4-0, but the Wildcats haven't exactly been perfect. They enter the bye week after an unconvincing 35-21 win over FCS school Maine, and they'll try to regroup in time for their next big test -- against No. 4 Ohio State on Oct. 5. Here are a few things they'll have to focus on to improve in time for the conference season:

1. Get tailback Venric Mark up to speed. Northwestern's option just hasn't been the same without Mark, who hasn't played since Week 1 because of a leg injury. He returned to practice Tuesday, however, and Pat Fitzgerald labeled him "day to day." The Wildcats' rushing attack has fared well in his absence, but Northwestern sure could use the running back who rushed for 1,366 yards and a dozen scores last season. Northwestern needs its best players for its best opponents, so Mark's progress here is paramount. This bye week is crucial to him healing.

2. Shore up the secondary. Pat Fitzgerald was thrown a curveball when cornerback Daniel Jones suffered a season-ending injury in Week 1, and the Wildcats' secondary just hasn't been able to rebound. Teams are targeting Jones' replacement, Dwight White, and Northwestern will have to find a way to neutralize opponents' passing games. The numbers just haven't been pretty so far. Northwestern ranks No. 115 in pass defense, allowing 308 yards a game, and that issue has caused problems elsewhere. Opponents are converting more than 44 percent of their third downs, which puts NU at No. 94 in that area. And their red-zone defense has been atrocious. Opponents, which include the likes of Maine and Western Michigan, have combined to score on all but one of their 14 trips to the red zone. Those aren't numbers expected of a Big Ten title contender.

3. Limit the turnovers. It's difficult to point too many fingers at an offense that's scored at least 35 points in four consecutive games. But turnovers have stalled too many Wildcats drives. They've committed seven turnovers already -- four interceptions, six fumbles (three lost) -- when they had just 15 all last season. In just the last three games, Kain Colter fumbled twice (neither lost) and threw two interceptions on 35 passing attempts. He has to protect the ball better or this trend could turn into a bigger problem. Northwestern was ranked within the top 15 last season when it came to limiting turnovers. This season? Tied for 82nd.