Without Lionel Messi, it's time for Neymar to step up on the big stage.

Barcelona will be without Messi for 7-8 weeks, starting with Tuesday's Champions League match against Bayer Leverkusen, after the Argentina forward injured his left knee.

''It's a shame for football,'' Leverkusen sporting director Rudi Voeller said. ''You simply like to watch him play.''

The last time Leverkusen played at Barcelona in 2012, Messi scored five goals in a 7-1 victory.

Messi was hurt on Saturday in the 2-1 win over Las Palmas in the Spanish league. Neymar played, but missed a penalty after Luis Suarez had already scored the opening two goals.

Because of the injury, Barcelona coach Luis Enrique faces the challenge of picking an attacking formation that will keep his team in competitions as Messi recovers.

''It's great news for our rival, but for us it's a test and we have to accept it and overcome it,'' Luis Enrique said. ''Injuries are the worst thing in football and they carry a special weight when it's Messi.''

In the other Group E match, BATE Borisov hosts Roma.

Here are some things to know about Tuesday's matches:

Minus Messi

Barcelona coach Luis Enrique has some decisions to make.

He can abandon his favored three-pronged attacking formation and instead opt for the security of an extra midfielder, or include Munir El Haddadi to support Suarez and Neymar up front.

El Haddadi, a 20-year-old Spain forward who is considered one of the brightest prospects in the game, has yet to score in four matches this season.

He did, however, supply Suarez with an assist against Las Palmas - the Uruguayan's fifth goal in nine matches. Neymar has scored three goals in six matches.

Improving Leverkusen

Bayer Leverkusen has recovered from its Bundesliga mini-slump of three losses with two straight victories.

The latest win was a 3-0 victory over Werder Bremen with Javier ''Chicharito'' Hernandez and Hakan Calhanoglu both on the bench at the start.

Solidarity

Messi won't be on the field, and the rest of the Barcelona team needs to get used to it.

''Like it or not, Messi is our best player, the one who causes the most problems,'' Barcelona defender Marc Bartra said. ''It's a major loss but now we have to become even stronger.''

Barcelona could also be without Jordi Alba and Thomas Vermaelen, who are injured.

Depleted Roma

Roma won over the weekend, but forwards Francesco Totti and Edin Dzeko went off injured during a 5-1 victory over Carpi and will be out for up to four weeks.

Also, midfielder Seydou Keita is expected to be sidelined for about two weeks after injuring his right thigh during the same match.

''We wanted the three points, but I would call it a Pyrrhic victory because of the three injuries after 50 minutes,'' Roma coach Rudi Garcia said.

It was a first win for Roma in four matches, including its opening Champions League draw against Barcelona.

Another positive was Gervinho finding the back of the net for the first time in almost a year. The Ivory Coast forward also hit the post.

''He's found confidence again and he can do great things up front,'' Garcia said. ''We have to be aware of our strengths and put them always on the pitch.''

Doubtful hleb

Alexander Hleb's return to BATE was supposed to give the team much-needed experience of playing at the top level.

However, Hleb was injured 30 minutes into BATE's opening 4-1 loss to Bayer Leverkusen with what the club has described only as a severe muscle injury. The former Barcelona and Arsenal midfielder has not played since and is an injury doubt for Roma's visit on Tuesday.

Since Hleb's injury, BATE has continued its steady progress toward a 10th straight Belarusian title - the club leads by 12 points with five games to play.

Defender Maxim Zhavnerchik and striker Vitaly Rodionov are also injured and unlikely to play against Roma.

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