The hosts must win to be assured of their progression from Group D, while the visitors have just a Europa League place to play for.
Atletico Madrid's four-game winless run - including three league games - has seen the Rojiblancos slip out of the top four and into seventh place in the La Liga table.
Diego Simeone's defensively-organised side have lost just two league encounters this term, but their eight draws see them eight points behind title-chasing pair Barcelona and Real Madrid despite having played a game extra.
Atletico boast - as usual - the best defence in La Liga, with just 10 goals conceded from 16 games. Concerningly, however, at the other end, they have the lowest tally of any side above 14th in the table, recording just one strike per game on average.
While Atletico's struggles in front of goal have followed them into Europe - with just six goals in five games - their defensive solidity has not, conceding a goal per game on average in the group so far and recording just two clean sheets in the process.
The Spanish side's European campaign had initially been going well, with two wins and a draw putting them in a comfortable position. However, back-to-back losses against Bayer Leverkusen and Juventus handed the former a lifeline and the latter qualification, meaning Wednesday's encounter now carries greater significance than it otherwise would have.
Simeone's side must at least match Leverkusen's result against Juventus, who have nothing left to play for as confirmed winners of the group and may play a rotated team, meaning a win at home over the side bottom of the group could well be necessary.
Lokomotiv also have something to play for, despite being unable to make the knockout stages of the Champions League. Should they beat Atletico, a Leverkusen loss could see the Russian side finish third in the group and make the knockout stages of the Europa League.
A 2-1 victory over the Bundesliga side remains their only points in the group so far, though, with four straight losses since then leaving them rooted to the foot of the table.
Additionally, they have lost their last three league games in the build-up to this fixture and are in woeful form, making the chances of an unlikely victory even more remote.
Atletico Madrid Champions League form: DWWLL
Atletico Madrid form (all competitions): LWDLLD
Lokomotiv Moscow Champions League form: WLLLL
Lokomotiv Moscow form (all competitions): LDWLLL
Atletico head coach Simeone is without several first-team regulars ahead of this match.
For Lokomotiv boss Yuri Semin, Joao Mario and Luka Djordjevic are definitely out, while Anton Miranchuk, Guilherme and Rifat Zhemaletdinov are all doubts but could feature. Dmitri Barinov is suspended.
Atletico Madrid possible starting lineup:
Oblak; Trippier, Felipe, Hermoso, Lodi; Correa, Saul, Thomas, Koke; Felix, Morata
Lokomotiv Moscow possible starting lineup:
Guilherme; Ignatyev, Howedes, Corluka, Rybus; Murilo, Krychowiak; Zhemaletdinov, Aleksey Miranchuk, Tugarev; Eder
We say: Atletico Madrid 1-0 Lokomotiv Moscow
While Atletico are in poor form, Lokomotiv's recent run is even worse and Simeone's side will expect to confirm their place in the knockout stages on Wednesday with a win. The Rojiblancos rarely blow their opposition away, however, and another low-scoring game could be on the cards.