Chelsea will face enormous pressure on Tuesday at Stamford Bridge. If allegations of air rifles at Cobham are heaping more pressure on manager Carlo Ancelotti, then a visit from Manchester United won’t do him any favors.

Chelsea enter this match sitting fifth in the table, two points behind fourth place Tottenham, and 15 points behind leaders United. Such gaps have been overcome before, but the reigning Premier League champions will know that a loss takes them further away from the top, but more importantly, keeps them one place away from qualifying for the Champions League.

While Ancelotti will be able to choose from the strongest possible side that he’s had in awhile, with only Alex and Yossi Benayoun unavailable due to injury, that hasn’t lessened his selection headaches for this crucial match. At the time of writing, Ashley Cole’s status is uncertain after the alleged gun incident that was reported on Sunday. Didier Drogba is also likely to be content with a spot on the bench as he has a slight knee problem and is still being eased back from malaria.

Sir Alex Ferguson’s selections aren’t any easier. Controversy surrounds Wayne Rooney as well, with the FA meeting to decide whether to issue a three-match ban to the Englishman after his blatant elbow to the head of James McCarthy in Saturday’s match against Wigan. Rooney was not sent off, but the FA may choose to act retroactively. Ryan Giggs status is also up in the air as he’s recovering from an arm injury, while Park Ji-Sung, Anderson, Rio Ferdinand, and Jonny Evans are also unavailable due to injury.

For Chelsea, the likelihood is that Ancelotti will return to the trusted 4-3-3 or Christmas tree formation. The 4-4-2 against Copenhagen worked well in attack, but conceded a lot of space between the midfield and defence. Should Rooney escape punishment, it’s the type of space that he can exploit. Expect a formation that employs a holding midfielder.

For United, they’ve had mixed results with different formations lately. While a 4-0 win over Wigan looks impressive on paper with the forward tandem of Rooney and Javier Hernandez yielding three goals, United’s midfield of Paul Scholes and Michael Carrick were outplayed for much of the first half and United were fortunate to have not gone behind before the half. Similarly, United’s draw with Marseille at the Stade Velodrome was also less than flattering as Ferguson’s three man midfield of Carrick, Fletcher, and Gibson were ineffective, leaving Berbatov isolated and Rooney running around on the left flank looking for the ball.

One of the major focal points, outside of tactics, is the £50m man, Fernando Torres. With young Chris Smalling partnering Nemanja Vidic in United’s central defence, the Spaniard may very well break his scoring drought since joining Chelsea. If there’s one center back that Torres has had the beating of in his career, its Vidic, who has seemed to be confounded by Torres pace and skill. If Torres can continue to show that Vidic is afraid of him, Chelsea will have an opportunity to get at him and the inexperienced Smalling to test Edwin van der Sar.

One last tidbit: United have not won at Stamford Bridge since 2002. On that day, United were paced by goals from Scholes, Ruud van Nistelrooy, and Ole Gunnar Solksjaer. Of the players that played in that match, only four remain: John Terry and Frank Lampard for Chelsea and Giggs and Scholes for United.