Arsenal may face a tough challenge in their upcoming Premier League match against Chelsea at the Emirates Stadium this Sunday, potentially missing two important players. Mikel Arteta's team has started their title defense strongly, defeating Coventry City and Aston Villa in their opening two games. However, they could be without Bruno Guimaraes and Cristhian Mosquera, both of whom did not attend training on Thursday. Guimaraes has already missed a game this season, sitting out Arsenal's opening league match against Coventry due to an injury sustained during the Community Shield final against Manchester City. He came on as a substitute in the game against Villa but may not be available for the Chelsea match. Mosquera, who started both of Arsenal's first two league games, was substituted late in the Villa match after suffering an injury. Arteta explained that the injury forced them to bring in Ezri Konsa, who joined from Aston Villa for £51 million in the summer transfer window. If Mosquera is not fit to play, Konsa could make his first start since joining the club. Arteta emphasized the importance of having depth in the squad, especially as the team competes in multiple competitions this season. He noted that the decision to substitute Mosquera was made to ensure the team's long-term health. Meanwhile, Chelsea may also be without midfielder Moises Caicedo, who was forced off after just 14 minutes in his substitute appearance against Brighton. Alonso mentioned that Caicedo felt unwell and chose to leave the game, but there is no indication of a new injury. The team will assess his condition during the week before making a final decision on his availability for the Arsenal match.