Moscow - Instead of keeping players fresh, Manchester United can't take any risks against CSKA Moscow.
All four teams in Group B have three points from two Champions League matches, leaving United little room to rest players ahead of the Sunday's derby against Manchester City.
United lost at PSV Eindhoven in the opening round, making the match against CSKA more important. The Moscow club took four points off City in the Champions League last year, but CSKA has long-standing defensive troubles in Europe.
In the other group match, Wolfsburg hosts PSV Eindhoven.
Here are some things to know about Wednesday's matches:
AT A CROSSROADS
CSKA is at the top of the Russian league and still very much in the hunt to advance in the Champions League, but the imminent departure of its coach could prove a major distraction.
Leonid Slutsky, who has twice taken CSKA to the Russian title, is set to leave the club for Russia's national team. He has been combining the roles of CSKA and Russia coach since August, when he stepped in to save a European Championship qualifying campaign which had faltered badly under Fabio Capello.
After four wins in four games, Russia has qualified for next year's tournament, but the Russian Football Union says it will not allow Slutsky to keep dividing his time between club and country. Negotiations are reportedly beginning for Russia to buy Slutsky out of his CSKA contract.
In an apparent piece of succession planning, former BATE Borisov coach Viktor Goncharenko has been brought in by CSKA as an assistant to Slutsky. With eight Belarusian titles to his name as player and coach, the 38-year-old Goncharenko is widely considered to be one of Eastern Europe's most promising coaches.
Wayne Rooney scored his first away league goal in 11 months in Saturday's 3-0 win at Everton and will hope that sparks a run after a slow start.
Also, United manager Louis van Gaal has no new injury problems, with defenders Phil Jones and Marcos Rojo returning.
After losing Kevin de Bruyne and Ivan Perisic at the end of the transfer period, Wolfsburg needed time to adjust but seems to be back on track.
Max Kruse and Julian Draxler, brought in as their replacements, have finally clicked. Kruse had a hat trick and Draxler set up two as Wolfsburg beat Hoffenheim 4-2 in the Bundesliga. Andre Schuerrle also contributed one goal.
But Kruse, who is also scoring for Germany again, was the big winner of the day, finally snapping his scoring drought after 841 minutes. Wolfsburg coach Dieter Hacking made him play as a "hanging striker," just behind point man Bas Dost, and that seems to be his favorite role.
Schuerrle will continue to find it hard to be a starter, but he's proven his worth coming off the bench.
PSV is likely to welcome back captain Luuk de Jong for its match against Wolfsburg after he recovered from an ankle injury.
The striker was injured for his team's 3-2 loss in Moscow two weeks ago, but made his return to first team action as a second-half substitute in Saturday's 1-1 league draw with Excelsior Rotterdam.
"The ankle feels good, so that gives me confidence," De Jong told Dutch daily De Telegraaf.
PSV, the 1988 European champion, is at the top of Group B on goals scored.