"We have 11 games to go and we have tricky away games," the Arsenal manager said.
The former beat Leeds United 4-1 while Manchester United got the better of Aston Villa 2-1 in the third round of the FA Cup.
The Chelsea winger sustained the injury when he landed heavily after being challenged as he shot at goal.
A summary of sports events and sports persons, who made news on Wednesday
A 1-1 draw at Charlton Athletic sent Arsenal back to the top of the premier league.
The Manchester United midfielders have knee injuries and will miss Champions League matches against Basel and Deportivo Coruna.
Manchester United's 3-0 victory over Fulham gave them the top spot in the English premier league.
Free-scoring Arsenal replaced Chelsea as Premier League leaders as goals either side of halftime by Theo Walcott and Mesut Ozil helped them recover from a slow start to beat Stoke City 3-1 on Saturday.
Stevan Jovetic and Jesus Navas scored their first goals for ManchesterCity who avenged last season's shock FA Cup final defeat by Wigan Athletic with a 5-0 victory in the League Cup third round on Tuesday.
Images from the EPL matches played on Sunday
Wales coach Chris Coleman conceded on Thursday that a stoppage-time loss to England was the low point of his career, but he said he could take inspiration from Roy Hodgson's side who had also come back from deep disappointment. Wales led at halftime after a sensational long-range Gareth Bale free kick, but lost 2-1 after Jamie Vardy's equaliser and Daniel Sturridge's winner in the 92nd minute. Asked whether this was the low point of a career that has included spells in charge at Fulham, Real Sociedad and Greek side Larissa in Greece, Coleman responded: "I'd have to say yes to be honest.
News of all that's transpired on and off the football field
Chelsea ripped apart Premier League title rivals Arsenal in a 6-0 mauling at Stamford Bridge on Saturday to ensure Arsene Wenger's 1,000th game turned sour and Liverpool and Manchester City kept up the pressure with big wins.
Zlatan Ibrahimovic has once again made the shortlist of for FIFA's goal of the year award, giving him a chance to retain the trophy he won last year.
Manchester City suffered their first home Premier League loss in eight months as a shock 3-2 defeat by Crystal Palace on Saturday left Pep Guardiola's champions trailing leaders Liverpool by four points.
Liverpool and champions Manchester City drew 0-0 at Anfield while Chelsea and Arsenal enjoyed comfortable away wins. City are top on goal difference from Liverpool and Chelsea with Arsenal two points behind.
Manchester United battled back from two goals down to beat Newcastle United 3-2 at Old Trafford on Saturday as a 90th-minute winner from Alexis Sanchez completed a spirited comeback to ease the pressure on manager Jose Mourinho.
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Eden Hazard scored from the spot in stoppage time to salvage a 2-2 draw for Chelsea against West Bromwich Albion, who were seconds away from inflicting a first Premier League home defeat on a Chelsea side managed by Jose Mourinho.
Liverpool's Mohamed Salah is willing to put his Champions League ambitions on the back-burner to help the Merseyside club claim their first English league crown in 29 years, the Egyptian forward has said.
IMAGES from the English Premier League matches played on Saturday
Manchester City thrashed Southampton 6-1 to remain top of the Premier League.
News of all that's transpired on and off the football field.
FC Pune City also bolstered their defence by signing former Espanyol and Deportivo La Coruna defender Diego Colotto for the second edition of the eight-team league beginning on October 3.
Images from the English Premier League matches played on Tuesday
Former Manchester United striker Andy Cole is recovering in hospital after undergoing a kidney transplant, the club said in a statement on Friday.
Former Cup winners Coventry, now plying their trade in the bottom division of the Football League, revived memories of happier times as Jordan Willis and Jack Grimmer scored the goals in a 2-1 victory at the Ricoh Arena.
David Beckham's 12-year-old son Romeo Beckham cashed-in 45,000 pounds for one day's work after modeling for high-end fashion brand Burberry, it has been revealed.
The spotlight on London football usually shines on glamour clubs Arsenal, Chelsea, Tottenham Hotspur or West Ham United but rarely on unfashionable Brentford who last played in the top flight nearly 70 years ago.
Premier League leaders Manchester City won their derby with United 3-1, while Liverpool kept pace with a home win over Fulham.
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Tottenham rejected Reece Oxford before he joined West Ham.
The injury to the Chile forward, who was left out of the squad for Tuesday's Champions League victory over Young Boys, "will require further investigation to confirm its severity", the club added.
A summary of Thursday's Euro 2020 qualifying matches.
Defending champions India dished out a listless performance but still managed to beat arch-rivals Pakistan 1-0 in the opening game of the SAFF Football Championship in Kathmandu on Sunday.
Marouane Fellaini scored late in extra time to spare Everton's blushes as they came from a goal down to beat League One (third division) Stevenage 2-1 and reach the League Cup third round on Wednesday.
Chelsea goalkeeper Kepa Arrizabalaga remains the club's first choice but manager Maurizio Sarri is still uncertain if the Spaniard will be recalled to the starting team for Sunday's Premier League trip to Fulham.
Premier League clubs Watford and Hull City, and Championship side Leeds United paid the penalty for fielding weakened teams when they were all knocked out of the FA Cup in the fourth round on Sunday -- but holders Manchester United won comfortably.
Late goals from Nicklas Bendtner and Theo Walcott spared Arsenal's blushes and kept them top of the Premier League in a 2-0 victory over Cardiff City as title rivals Manchester City and Chelsea also won on Wednesday.
Arsenal maintained their challenge for a first trophy in nine seasons when they beat Liverpool 2-0 at the Emirates Stadium to open up a five-point lead at the top of the Premier League on Saturday.