Before yesterday's set of games, it looked like MSU and OSU had the opportunity to go undefeated through the season. OSU would have won the bid to the Rose Bowl because of the 3rd tiebreaker in the conference (BCS). OSU lost last night, so now it looks like MSU is in position to go to the Rose Bowl. Even if they have a Sparty, No! game against a lesser opponent, tie breakers give them the go ahead for the Rose Bowl.
Here are the rules for determining the Rose Bowl bid:
1. Conference record
3. Overall record
4. BCS rank in final poll.
Here are the teams that could still potentially win the Big Ten, i.e. they have 1 loss are undefeated in the Big Ten:
MSU 3-0 (7-0)
Iowa 2-0 (5-1)
Purdue 2-0 (4-2)
Wisconsin 2-1 (6-1)
OSU 2-1 (6-1)
NW 1-1 (5-1)
I don't think anyone would argue against taking Purdue and NW out of the discussion. One looks horrible and the other lost to the first one. This isn't to say they can't have an effect on the other teams, but that they are unlikely to win the rest of their games in the conference.
So, now we have MSU, Iowa, Wisconsin, and OSU. For the purposes of this post, let's assume that none of them lose to any teams not in this list. Obviously, this can happen, but it is unlikely and has a small probability of happening.
Between these 4 teams, there are 6 possible matchups. 2 have been played (MSU vs. Wisconsin, Wisconsin vs. OSU), 1 will not be played (MSU vs. OSU), and 3 are still to come (Iowa vs. MSU, Iowa vs. OSU, Iowa vs. Wisconsin). As you may have noticed Iowa has not played any of the other 3 teams, therefore, they can essentially decide who goes to the Rose Bowl with which games they win and lose.
If Iowa loses to MSU, MSU goes to the Rose Bowl. MSU would have Head-to-Head advantage over the other 3 teams, not to mention a 1 game lead.
If Iowa beats MSU, there are 4 possibilities:
Beat OSU, Beat Wisconsin: Iowa is the only undefeated team in the Big Ten. They are in the same situation that MSU is if MSU wins their matchup.
Beat OSU, Lose to Wisconsin: Three-way tie between MSU, Wisconsin, and Iowa in conference record and Head-to-Head. Iowa gets eliminated for their loss to Arizona. MSU wins the Head-to-Head against Wisconsin.
Lose to OSU, Beat Wisconsin: 3-way tie between OSU, MSU, and Iowa. OSU wins the Head-to-Head round.
Lose to OSU, Lose to Wisconsin: 3-way tie between MSU, OSU, Wisconsin. MSU wins the Head-to-Head round.
In 6 of 8 scenarios, MSU wins the Big Ten. If Iowa beats MSU, the only way they win the Big Ten is if Wisconsin beats Iowa. OSU is hoping for the perfect storm where Iowa takes down MSU and Wisconsin for them and also bends over for them. Wisconsin's only hope right now is for MSU to Sparty, No! this season. Ironically, Wisconsin's Big Ten hopes were probably over before they started.