Stoke City have suffered an injury blow a week before hosting Coventry City in the opening Championship game of the season, with big summer signing Sam Gallagher a doubt to make his competitive debut at the bet365 Stadium.

The 28-year-old striker, who joined the Potters for an undisclosed fee from Blackburn Rovers last week, lasted just 28 minutes in the club’s final pre-season friendly at the weekend – a 1-0 defeat to AZ Alkmaar.

Gallagher led the line with Million Mandoef and Lynden Gooch on either side but went to ground off the ball, holding his calf just before the half hour mark. The ex-Southampton striker was down for a short while as the medical team went to treat him, before hobbling off the pitch and being taken off, with Niall Ennis replacing him.

That sparked concern over his fitness, just a week before their Championship curtain-raiser against the Sky Blues but Stoke boss Steven Schumacher has got his fingers crossed that the centre-forward hasn’t done too much damage, having impressed during his time on the pitch.

When asked about how Gallagher is, Schumacher said: “I am not sure, he just said that he felt his calf. It was tightening up a bit during that first half. He sat down pretty much straight away as he did it, so fingers crossed it’s not too serious but he came off with a stiff calf.”

He added: “It’s not worth it (taking risks). We’ve had a couple of niggles with a few of the lads late on in pre-season. Normally it happens earlier in the pre-season, but we have had a couple of them late on but it’s part and parcel of football, it happens and we’ve got to make sure we have everybody in as best condition as we can for the weekend.”

Elsewhere, Ryan Mmaee suffered a set-back just as he was about to return to Stoke’s team for the first time in almost four months.

Mmaee missed the final few weeks of last season with a hamstring injury and has been working with the fitness staff on a knee injury through the summer. He returned to full training at the end of July and was hoping to make his comeback to play a part in the friendly at Bolton Wanderers only to fall ill with tonsillitis, and wasn’t involved at the weekend.