Although Arsenal's victory over West Ham was a huge boost to their title challenge, it did not come at no cost. The introduction and subsequent impact of Lukas Podolski has grabbed the headlines, but the German only took to the field to replace the injured Aaron Ramsey.
Ramsey has been Arsenal's best player this season, and with 13 goals in all competitions, the Welshman is their top scorer as well. However, as soon as he pulled up against West Ham, he knew he had a significant problem. His hand gesture to the bench suggested a muscle pull, and in his press conference, Arsene Wenger confirmed the severity of the injury.
Speaking to Arsenal.com after the game, Wenger said:
It looks [serious]. It looks like a thigh strain. I don't know how serious the thigh strain is but the Christmas period certainly is over for him. It was his birthday today. I don't know how long he will be out for. We will know tomorrow morning. He knew straight away but we will have to see.
As yet, Arsenal have made no official announcement about Ramsey's prognosis. However, it seems certain he will miss the forthcoming games against Newcastle, Cardiff and Tottenham Hotspur.
One option could be to replace him with Podolski, like yesterday, and shift Santi Cazorla back into central midfield. However, Arsene Wenger would be loathe to use such attacking tactics on a regular basis.
Having conceded the opener to West Ham, Arsenal were chasing the game and forced to gamble. It nearly proved costly: West Ham had several opportunities to extend their lead on the break.
After the match, Wenger explained to Arsenal.com: "On the pitch we had Podolski and Walcott and Giroud and Ozil and Cazorla you know when you lose the ball you can be a bit vulnerable but we had to go for it".
That concern over Arsenal's defensive vulnerability will probably prevent Wenger from introducing Podolski as a straight replacement for Ramsey in his first XI. For Wenger, balancing the side is of vital importance.
With that in mind, Wenger is more likely to opt for the returning Jack Wilshere or fellow Frenchman Mathieu Flamini to replace Ramsey.
Wilshere's availability after suspension comes at a perfect time. Having been forced to sit out the last two games on the sidelines, he will be eager to re-establish himself in the team. Ramsey's absence could allow Wilshere a run in his preferred central position.
At his best, Wilshere offers a similar creative threat to the Welshman. He has also begun to add goals to his game: Wilshere has four already from just 17 starts.
Alternatively, Wenger could turn to the reliable Flamini to play alongside Mikel Arteta. While Flamini lacks Wilshere's guile and invention, he would make up for Ramsey's hustling energy and increasingly effective tackling.
Flamini has already made nine Premier League starts this season, and has shown himself to be a combative and committed performer. With the Gunners set for a stern test against in-form Newcastle, deploying Flamini could help give Wenger's team a solid platform at the heart of the midfield.
Flamini and Wilshere have different styles, but both could help Arsenal fill the void created by Ramsey's absence.
James McNicholas is Bleacher Report's lead Arsenal correspondent and will be following the club from a London base throughout the 2013/14 season. Follow him on Twitter here.