Arsenal forward Alexis Sanchez doubtful for FA Cup tie against Middlesbrough

Arsenal are likely to again be without Alexis Sanchez for the FA Cup fifth-round visit of Middlesbrough as the Chile international continues to nurse a knee problem picked up in the midweek win over Leicester City.

Sanchez was substituted after 69 minutes of the 2-1 win on 10 February with a knee problem and wrote a cryptic message on Twitter, saying: "Sometimes the love for the game and anxiety to be on a football pitch works against you."

After missing the win over Stoke City and loss to Tottenham Hotspur due to a hamstring problem, Arsenal's top scorer is facing another spell on the sidelines after manager Arsene Wenger claimed he would likely be "short" for the visit of Championship side 'Boro.

Alex Oxlade-Chamberlain and Aaron Ramsey will definitely miss the tie with respective injuries, with the latter suffering a hamstring blow in the win over Leicester and Wenger admits the club will continue to investigate the reason for the Welshman's continued injury issues.

"We haven't found an underlying reason," he said. "There's certainly a medical or biomechanical reason. He is a guy who is serious, works hard and has a disciplined life. There's no obvious reason why he should have muscular problems.

"We have individual training for the player and prevention and this should not be a special case we just have to find a reason why it happen. It's grade one, not a serious injury."

Jack Wilshere back in training

There is some positive injury news for Arsenal ahead of the spark end of the season with Jack Wilshere has returning to training after four months out following ankle surgery.

"He's motivated and focused to come back as quick as possible," Wenger added. "He worked very hard but he has still been out for to four months and what he need is to get back. He needs competition.

"This is a period where you need more from your players than usual, because it's the last four months of the season. Some players will play who have not played recently but we will treat this game exactly the same as a Premier League game."

Wenger also confirmed Wojciech Szczesny will replace David Ospina for the match on 15 February, while January signing Gabriel Paulista is likely to make his debut at the heart of the Arsenal defence as the French boss plans to ring the changes.

On 10 February, the Premier League confirmed the renewal of its domestic television contract, with Sky Sports and BT Sport paying a combined £5.1bn for the rights to show matches over a three-year period from the 2016-17 season, a 70% increase from the last agreement.

The massive deal has sparked debate as how the influx of money could affect the running of the top flight clubs and Wenger says the extra cash will see Premier League sides strive to attract the world's best players in the transfer market.

"It looks to me a very impressive number," he said. "The extra Premier League money will contribute to getting more of the best players to play in England."