Ok so here is a table detailing all the undefeated and winless teams up to the start of week 3:
Undefeated Teams Start of NFL Week 3
Team Wk3 Wk4 Wk5 Wk6 Wk7 Wk8
Arizona Cardinals WAS NYJ BUF X DAL X BYE CAR X
Baltimore Ravens CLE PIT X TEN X IND MIA OAK
Buffalo Bills OAK STL ARI X BYE SD MIA
Carolina Panthers MIN ATL KC TB NO ARI X
Dallas Cowboys GB X WAS CIN ARI X STL TB
Denver Broncos NO KC TB JAC NE X BYE
Green Bay Packers DAL X TB ATL SEA IND BYE
New England Patriots MIA BYE SF SD DEN X STL
New York Giants CIN BYE SEA CLE SF PIT X
Pittsburgh Steelers PHI BAL X JAC BYE CIN NYG X
Tennessee Titans HOU MIN BAL X BYE KC IND
Winless Teams Start of NFL Week 3
Team Wk3 Wk4 Wk5 Wk6 Wk7 Wk8
Cincinnati Bengals NYG CLE X DAL NYJ PIT HOU X
Cleveland Browns BAL CIN X BYE CLE WAS JAC
Detroit Lions SF BYE CHI MIN X HOU X WAS
Houston Texans TEN JAC X IND MIA X DET X CIN X
Jacksonville Jaguars IND HOU X PIT DEN BYE CLE X
Kansas City Chiefs ATL DEN CAR BYE TEN NYJ
Miami Dolphins NE BYE SD X HOU X BAL BUF
Minnesota Vikings CAR TEN NO DET X CHI BYE
San Diego Chargers NYJ OAK MIA X NE BUF NO
Seattle Seahawks STL X BYE NYG GB TB SF
St. Louis Rams SEA X BUF BYE WAS DAL NE
Apologies for this being so messed up but I don't know how to insert a table
These are the only teams the system can either back or back against. As soon as the they are no longer undefeated or winless they come out of the portfolio for another year.