Arsenal are set to face Brentford today in a chance to go top of the Premier League table, but they may be missing Gabriel Martinelli. The Brazilian was withdrawn with a knock in last week’s victory over Sheffield United, and Mikel Arteta claimed that it was touch-and-go for the winger. With a crucial Champions League tie against Porto coming up on Tuesday, today’s game could be a chance to rotate a few players, with Jorginho another player who could benefit from coming into that game fresh. Emile Smith Rowe and Reiss Nelson were both unused substitutes against Sheffield United, but if Martine…