Stoke City manager Mark Hughes has confirmed Ryan Shawcross and Xherdan Shaqiri are unavailable for Saturday's Premier League match at Watford.
Shaqiri pulled a thigh muscle in last weekend's 2-1 home loss to Southampton, while Shawcross suffered a fresh back injury on his return from eight games out with a separate back problem.
"Ryan Shawcross won't be available. Shaqiri is likely to be missing for 10 more days or so," Hughes said. "Erik Pieters hasn't trained up until today, but hopefully we can get him out tomorrow. Other than that it is just long-term injuries.
"It can be difficult especially when you have multiple injuries in the same position. We have had to move people around a lot.
"When we have had a steady back four - a continuity - we have been very good and looked really solid.
"It is no coincidence that when you look at Leicester, who have been able to play the same team week in week out, that they are at the top of the league. We haven't had that luxury, sadly."
Defeat to Southampton was a blow to Stoke's continental ambitions, but Hughes remains focused on securing a place in next year's Europa League.
"Make no bones about it, if we ever got in a position to get into the Europa League then we would approach it as a priority," he said.
"I can understand people questioning the difficulties of playing Thursday and Sunday, having maybe travelled across the continent, but we would take that inconvenience just to experience it again.
"We enjoyed the moments in Europe a few years ago and I would love to take Stoke back there. Look at the clubs who are involved in that competition - huge European clubs, so we would love to pit our wits against them.
"The next step for us is to challenge for European football each season."
Hughes added that goalkeeper Jack Butland is "close" to signing a new contract to stay at the Britannia Stadium.