Bayern Munich coach Jupp Heynckes hopes Thomas Muller's injury is no more than cramp after the forward lasted just 10 minutes of his side's 1-0 win at Hamburg.
Muller came on as a second-half substitute, replacing James Rodriguez, but had to be withdrawn soon after with Heynckes sending Thiago Alcantara on for the Germany star.
Bayern won the game 1-0 courtesy of Corentin Tolisso's goal in the 52nd minute, for which Muller provided the assist.
When asked why he took Muller off, Heynckes told Sky Germany: "He had a cramp. I hope it's only that.
"We have to wait until the check-up tomorrow."
Heynckes admitted Hamburg frustrated his side in the first half, but the game opened up following Gideon Jung's second-half sending off.
"Hamburg were highly motivated," said Heynckes. "In terms of fighting they were amazing.
"We had problems in the first half. We didn't have the high tempo we wanted.
"After the break it was better as we had four clear chances to score."
The victory left Bayern level on points with Bundesliga leaders Borussia Dortmund after they were held to a 2-2 draw by Eintracht Frankfurt, something the defending champions were well aware of before their clash at the Volksparkstadion.
"It was a very important game," said Heynckes. "We knew the result from Dortmund before, but we couldn't bring everything we wanted on the pitch.
"In the end it was a very tight game."
Meanwhile, Hamburg midfielder Jung questioned the referee's decision to show him a straight red card for a challenge on Kingsley Coman.
He told ZDF: "It was not my intention to hurt a player and hurt my team. With a man down, it is hard.
"It can be a card, but I think in the situation and the course of the game, it was not necessary."
21. Mai 2018
|If you Googled ´European nights´, Liverpool would be top result - Klopp|
|BREAKING NEWS: Icardi cut from Argentina World Cup squad|
|Test recall a ´fantastic surprise´ for Buttler|
|Klopp needs Premier League to be a Liverpool great – Johnston|
|Salah is ´definitely´ world´s best - Lovren|
|Rhinos captain Watkins ruled out for eight months|
|No clue - Klopp defiant over Can to Juventus claims|
|Younis tips Babar for Pakistan greatness|
|Germany squad numbers hint at World Cup good news for Neuer|
|WATCH: Moto3 rider makes spectacular jump over crashed rival|
|Leaving out Morata ´painful´ for Spain boss Lopetegui|
|Gustard to leave England role for Harlequins|
|Nainggolan retires from Belgium duty after World Cup snub|
|Spain striker Morata misses out on World Cup selection|
|LeBron or Kawhi could lead Lakers to the Finals - World Peace|
|Serena steps up Roland Garros training ahead of French Open|
|Nainggolan left out of Belgium´s World Cup squad|
|The long goodbye: Iniesta sits alone in Camp Nou after final Barcelona match|
|Wane to leave Warriors at end of season|
|Dr Fury will see you now - Tyson plans future career in medicine|
|Harden, D´Antoni rue ´soft´ Rockets performance in Warriors drubbing|
|Liverpool players can change their lives in Kiev, says Gerrard|
|Real Madrid v Liverpool: Can great deeds of the past fuel the bid for Champions League glory?|
|Wash your mouth out! - Curry´s expletive outburst earns scolding from mother|
|Rakitic lost for words as Iniesta heads for Barcelona exit|
|Conte: Chelsea must overhaul squad to change style|
|Johnston: Liverpool can´t lose Suarez, Coutinho and Salah!|
|Messi: I like Griezmann, he´s one of the best|
|Ohtani says he´s not good enough for Home Run Derby yet|
|Mendy: France are eyeing World Cup glory|
|Scott accepts two-week ban for Walker punch|
|Braves rally for six runs in the ninth to defeat Marlins|
|MLS Review: Red Bulls upstage Atlanta thanks to Wright-Phillips brace|
|Warriors breeze past Rockets in game three|
|We have a quality squad – Man City chairman hints at caution in transfer market|
|Wise cruises to maiden PGA Tour victory at Byron Nelson|
|Matic: United can fight for Premier League and Champions League with experience|
|Golden Knights GM on Stanley Cup Finals berth: I don´t know how we did it|
|I did a ´s*** job´ defending LeBron James – Morris|
|Dembele suffers sprained right ankle|
|We know Fellaini´s not going to renew with United – Mirabelli suggests Milan move|
|Cavs´ Lue not satisfied with just one win|
|They even whistled at Torres – Simeone backs Griezmann|
|I arrived as a boy, I leave as a man – Iniesta in emotional Barcelona farewell|
|Lingard: Wembley loss my worst feeling in football|
|Cahill: Conte uncertainty affecting Chelsea|
|Sarri has run out of time – Napoli chief De Laurentiis|
|Barca boss Valverde salutes departing Iniesta|
|I feel like I´ve been run over by a truck or had 15 pints - Crutchlow|
|Four sent off as Ajaccio win chaotic Le Havre play-off on penalties|
20. Mai 2018
|Sweden win shoot-out to retain world title|
|De Vrij penalty was destiny for Inter - Icardi|
|PSG? Maybe one day - Pogba coy over long-term future at Manchester United|
|Messi wins fifth European Golden Shoe|
|Gattuso calls for more malice at Milan|
|Barcelona 1 Real Sociedad 0: Coutinho stunner lights up Iniesta´s farewell|
|Lazio 2 Inter 3: Spalletti´s men seal Champions League qualification with stunning comeback|
|Royals reach play-offs as Kings XI come up short|
|Nadal sees clearly after Rome rain is gone|
|Double whammy for Zverevs as Mischa bows out in Geneva|
|Atletico Madrid pay fitting tribute to tearful Torres|
|Hull FC claim derby spoils, Dragons off the bottom|
|Buzarnescu battles through as McHale impresses in Nuremberg|
|Neymar an artist who will not need special treatment - new PSG coach Tuchel|
|Atletico Madrid 2 Eibar 2: Torres bows out with a double|
|Napoli 2 Crotone 1: Milik and Callejon condemn visitors to the drop|
|Iniesta starts on Barcelona goodbye but Messi rested|
|Nadal rallies after rain break to dethrone Zverev in Rome|
|AC Milan 5 Fiorentina 1: Cutrone brace secures Europa League group stage spot|
|I think I made a fantastic decision - Garoppolo key to Sherman joining 49ers|