Wayne Rooney has warned Bukayo Saka and Gabriel Martinelli that getting back into Mikel Arteta's Arsenal team may prove harder than expected.
Both players are currently sidelined with hamstring injuries.
Saka has been out since December when he needed to undergo surgery, while Martinelli has not played since limping off during last month's 2-0 defeat at Newcastle.
Martinelli is expected to return before Saka but neither is likely to be back in action until April.
Despite missing Saka and Martinelli - as well as Kai Havertz and Gabriel Jesus, who are also both injured - Arsenal thrashed PSV Eindhoven 7-1 away from home in the first leg of their Champions League round of 16 clash on Tuesday night.