Ollie Robinson has been ruled out of England's series decider against West Indies after failing to recover from a back injury.
The Sussex seamer missed out on the drawn matches in Antigua and Barbados and will play no part in Grenada as England chase a first Test win in nine attempts.
England confirmed their squad on Wednesday, a day before the third Test begins, with Craig Overton recovering from illness to replace Matthew Fisher in the only change.
Robinson was unable to prove his fitness in a net session and skipper Joe Root is hopeful his team-mate can soon put his fitness issues behind him.
"Ollie wasn't as good as we would have liked or he was expecting himself," Root said prior to the squad announcement.
"It's just frustrating for him, as it is for me. He's working very hard but there's something that's nagging away at him.
"I'm not sure exactly of the medical prognosis. He's just got to keep on doing what he's doing and trust in time that he's going to get himself back.
"We all know how effective he has been and how good he's been in his short career up to now so the sooner we can get him back the better."
Root is 116 runs short of reaching 10,000 in Test cricket, a tally only Alastair Cook has previously reached among England players.
The 31-year-old hit centuries in the opening two Tests against West Indies but could not help his side to victory, something he is looking to put right in this winner-takes-all clash.
"I really hope we can take another step forward as a team and get across the line because there's been a lot of good stuff," he told reporters.
"We've played the majority of the cricket up to now and it would be a great way to end the tour. The most pleasing thing is we've not had a nightmare session that's cost us a Test.
"We've looked at each individual session and each hour and looked to win each and every one of them."
England are unbeaten in their last three away Test matches against West Indies, having lost each of the three games prior to that run.
Their most recent meeting at St George's was in April 2015, with England claiming a nine-wicket victory.