Bayern Munich and Chelsea both enter the 2012 UEFA Champions League final weaker than they'd ever like.
Key players for both squads are suspended due to bookings throughout the tournament, and there is a great chance an unlikely hero makes his presence felt before the final whistle blows.
There is also a great chance that a reserve or two for both clubs plays a huge role in the outcome of this match.
The 22-year-old German burst onto the scene at the 2010 World Cup and has been a great weapon for the club when they need a boost.
Chelsea's back line is going to be without captain John Terry and Branislav Ivanovic; they're forced to start two players in the centre, David Luiz and Gary Cahill, who are coming off injury. Both players have starting experience, but it remains to be seen if they'll find solid form.
The Germans' midfield and attack will likely be Franck Ribery off to the left, Arjen Robben to the right, Bastian Schweinsteiger and Toni Kroos in the middle and Muller just off Gomez up top.
This lineup screams of a German onslaught against the Chelsea back line and keeper Petr Cech.
And if Muller isn't used in the starting XI, he'll be the first sub in the second half to provide a boost. Either way, he'll be a huge factor in this match.
As for the Blues, they'll start Didier Drogba up top, but eventually Roberto Di Matteo will give recently on-form star Fernando Torres a chance to shine—he could even put the two in the same lineup.
The West Londoners' defense will have to hold as any subs they make will come in the midfield or up top.
Depending on how the first half shakes out, the subs will be the key to this match.
This title tilt has no shortage of drama. Expect the use of fresh legs to make an impact for better or worse.