No fewer than seven players won't be on the pitch: Raul Meireles, Ramires, Branislav Ivanovic and John Terry for Chelsea and Holger Badstuber, Luiz Gustavo and David Alaba for Bayern.
That's why previous performances are less useful when trying to assess how the game might go. After all, players matter and if the guys on the pitch on Saturday night are different from those who came before them, historical results are irrelevant.
So who is worse off? On the surface, it's Chelsea. They have more players out. And, on top of that, two more central defenders, David Luiz and Gary Cahill, are injured. They may yet be fit for the Bayern game – in fact, they likely will be – but the fact is that it will have been a month since they last kicked a ball in anger.
Chelsea have little choice. Luiz and Cahill will start, with Jose Bosingwa slotting in at right-back. Effectively, compared to the hypothetical best back four, you're replacing Terry and Ivanovic with Cahill and Bosingwa. And that doesn't represent a huge drop-off: indeed, compared to the Terrry we saw against Liverpool last Tuesday, it may actually be an upgrade.
Meireles and Ramires are probably Chelsea's best box-to-box players, but their absence simply means Roberto Di Matteo will have fewer tactical options; it doesn't necessarily mean the side will be qualitatively worse. Michael Essien can fill in for the Portuguese if Di Matteo goes for three central midfielders, with either Florent Malouda or Salomon Kalou coming in for Ramires. And if he goes for the 4-2-3-1, he can stick Juan Mata behind Didier Drogba and pick two from Daniel Sturridge, Malouda and Kalou to fill out the wings. It's not ideal of course, but at least he has bodies.
Not so Jupp Heynckes. Central defence, with the Badstuber-Jerome Boateng partnership, was already Bayern's weakest area of the pitch. With Badstuber out, he has no reserve central defenders to call upon. Daniel Van Buyten has been sidelined since January 20. He did play just over an hour for Bayern's amateur side on Friday in his comeback game, but he is 34 and most agree it would be a huge gamble to send him out against Drogba on Saturday. Breno, another central defender, is injured, but, even if he were fit, his participation is unlikely: he's currently facing up to 15 years in prison for setting fire to his own house.
Luiz Gustavo has filled in well at centre-half, but he's suspended too. Nor can relief come from converting one of the full-backs. Alaba, of course, is also banned. Phillip Lahm is 5ft 7in and is needed on the flanks. Rafinha is roughly the same size, Diego Contento is 5ft 9in but has never played centre-back. Plus, one of the two will be needed to man the side opposite Lahm.
The only other solution is Anatoliy Tymoschuk, a defensive midfielder who isn't exactly a giant either at 5ft 11in. Tymoschuk, 33, signed with much fanfare on a Bosman in 2009, has been a disappointment. When he has filled in at the back, he has looked slow and awkward.
This means Heynckes can either go with the ageing, slow central defender who could break down again at any moment (Van Buyten) or the aging, slow midfielder (Tymoschuk). Either way, this is one final which likely won't be cagey and defensive. Expect goals.
Funny how football works. Di Matteo could lead Chelsea to victory in the Champions League and be out of a job a few days later. His side have already won the FA Cup, but he may pay the price for their wretched league position. As ever, nobody knows what the Chelsea owner, Roman Abramovich, is going to do, but what is not in doubt is that Di Matteo has been given no assurances that he will be back next season.
If he is relieved of duty, he may find a kindred spirit in his opposite number at the AllianzArena. Fourteen years ago, Heynckes was in the same position. He was the Real Madrid manager who had steered the club to fourth place in La Liga – an unacceptable finish according to the president, the media and many of the supporters. But he had also taken Real to the final of the Champions League. And, like Di Matteo today, he knew that his job probably did not depend on the outcome of the game. As it happened, Real upset a heavily favoured Juventus side in the final. Eight days later, once the festivities had ended – it was, after all, Real's first European Cup in 32 years – he was unceremoniously sacked.
Ninety minutes to settle the Premier League title race today, with Manchester City hosting Queens Park Rangers and Manchester United travelling to Sunderland. It's the nature of this game that instant verdicts and broad conclusions will be drawn on the basis of what happens today.
If City somehow stumble – and, it would basically take United bettering their result – the season will be remembered as a failure. Roberto Mancini might lose his job. That's what happens when you spend hundreds of millions and demand instant success.
Equally though, if he delivers the first title to the blue half of Manchester in 44 years, he'll go down in history as some kind of genius. And few will remember Sheikh Mansour's massive spending.
The range of reaction to United will be more limited. After all, even the most knee-jerk of critics have to give Sir Alex Ferguson some leeway for a quarter century of success.
Yet let's not forget what United have achieved this season in getting this far. The goalkeeper, David De Gea, is 20 and in his first Premier League season. Their best defender, Nemanja Vidic, has been out since December. Their young defenders – Rafael, Phil Jones and Chris Smalling – have played like, well, young defenders (and injuries haven't helped). Central midfield is so undermanned that Paul Scholes, at the age of 37, had to come out of retirement to help out. That's what happens when Darren Fletcher and Anderson – two guys who were rewarded with huge contract extensions 18 months ago – play a total of 62 league minutes since November.
Whatever happens today, Sir Alex has shown – once again – that he's the benchmark against whom all others are judged.