Arsenal are sweating over the fitness of Gabriel Martinelli after the forward suffered a gruesome looking injury in the warm-up against Newcastle.
Martinelli was due to start in the FA Cup third round clash at The Emirates on Saturday, but was forced out of the lineup after a nasty fall.
The 19-year-old tumbled to the turf in agony after twisting awkwardly when passing the ball to a teammate.
Physios assessed the damage and gave Martinelli treatment on his ankle, but he was replaced in the starting XI by Reiss Nelson as Arsenal urged on the side of caution.
Martinelli has only just returned to the Arsenal side following a six-month injury layoff, making just four appearances since making a full recovery.
Former Gunners striker Ian Wright was on punditry duties for the BBC, and said: "It's a massive blow that Gabriel Martinelli has been injured.
"He gives Arsenal and Mikel Arteta that energy. To see him go down it was really quite worrying."
The youngster has been key to Arsenal's recent revival, playing in both wins over Chelsea and Brighton that kick-started their run of good form.
Mikel Arteta opted to leave Martinelli on the bench for the victory over West Brom, but brought him back into the side for the FA Cup clash.
Nelson took Martinelli's place on the left flank, alongside Willian and Nicolas Pepe in a three-pronged attack behind captain Pierre-Emerick Aubameyang.
Joe Willock and Cedric Soares were also handed chances to impress in the fixture as Arteta looked to give some of his key stars a rest.
Emile Smith-Rowe, Bukayo Saka and Alexandre Lacazette were the chief beneficiaries, with the important trio all among the substitutes.
