John Guidetti, on loan from Manchester City to Stoke City, has expressed frustration about his lack of football under Mark Hughes and said the club will "have a problem" if he is left out of their next game, at Sunderland on Wednesday.

Guidetti, desperate to resurrect his career after a freakish illness ruled him out for the best part of two years, admitted being angry he had been an unused substitute in Stoke's FA Cup defeat at Chelsea on Sunday.

The 21-year-old Swede was a 79th-minute substitute in their game at Crystal Palace the previous weekend and told the Swedish newspaper Expressen: "It's been two games and we haven't scored. What is the worst that can happen [if I came on], that I don't score, or … ? We have to see what it is like for the next game, otherwise we have a problem."

Guidetti had missed training towards the end of last week because of a stomach complaint but said he was ready to play. "You are a bit angry [when you are left out]. I feel really good and the training sessions have been as good as they could have been. I had a stomach bug, I woke up on the Thursday with something to do with my stomach. So I hadn't trained since Thursday. But still, I travelled [to Stamford Bridge].

"I know what's in his [Hughes's] mind, that it is about the stomach, that I haven't trained. I can understand that a little bit. But I got a lot of positive feedback after the last game. That felt good. I had minutes against Crystal Palace and everyone thought I did bloody well. Then you think you are going to get the chance again. If we'd been banging in the goals you maybe could understand it.

"It is a cup tie. It doesn't matter if we concede another goal. I thought it was a little … you're angry, I don't really understand it. I feel really good otherwise, training has been going really well. Then it is difficult to do anything when you don't get to play."