By Daniel Orme Arsenal star Gabriel Martinelli is a major worry ahead of Tuesday’s clash with Porto after being spotted on crutches. The Brazilian was ruled out of the weekend’slate victory against Brentford at the Emirates Stadium. He was sidelined with a ‘foot issue’ that he picked up against Sheffield United last week \- Martinelli being helped from the pitch late on at Bramall Lane. It appears that the injury is more severe than first thought. During Saturday’s win against the Bees, he was spotted wearing a protective boot and was walking with crutches. Should he not recover in time, then …