Joyce, in the second over of England's two-run Twenty20 defeat against Sri Lanka at the Rose Bowl on Thursday, slipped going for a catch at third man and his right ankle gave way underneath him.
It was later revealed the Irish-born Middlesex batsman had suffered soft tissue damage after spraining his ankle but X-rays had shown no fracture.
Nevertheless his injury put a question mark against Joyce's participation in the five-match series with Sri Lanka starting at Lord's on Saturday.
Joyce, who only made his England one-day debut against Ireland on Tuesday after several years qualifying for his adopted country, joined a sick list already featuring another debutant against Ireland in 32-year-old pace bowler Glen Chapple (abdominal muscle), as well as pacemen James Anderson (back) and Simon Jones (knee) together with left-arm spinner Ashley Giles (hip).
And England are being captained, for the moment at least, by Andrew Strauss because star all-rounder Andrew Flintoff (ankle) and batsman Michael Vaughan (knee) are unfit.
"I don't know where to turn," Fletcher said Friday. "Poor old Ed Joyce has taken some time to qualify then gets his game and is injured.
"Glen Chapple has been on the fringe for some time, suddenly makes it, and is then injured and it just keeps going on and on."
Joyce went to see a specialist Friday as England pondered whether to call up a replacement.
"It is a big jump up but they'll just have to fill that gap," Fletcher said of possible newcomers to England's One-day side.
Unlike their Test team where, in recent years, the likes of Strauss, Alastair Cook and Monty Panesar have all found their feet quickly, England have struggled to blood new players in the one-day game.
In 2005 England won just eight of their 22 one-day internationals while earlier this year they slumped to a 5-1 limited overs reverse away to India - worrying signs ahead of next year's World Cup in the West Indies.
"A lot of the time we've been without our most experienced players in the one-day game, guys have got injured in Test matches and gone home," Strauss told reporters at Lord's here Friday.
"That doesn't help but, if we're honest with ourselves, we'd say we haven't played quite to our capabilities, certainly in the last two away series (against Pakistan and India).
"But we did pretty well against Australia last year (where England tied the one-day series final at Lord's), the best side in the world.
"That shows we are capable of beating any side, all we have to do now is get that consistency," the left-handed opener explained.
"Test cricket, from a batsman's point of view, you can play your natural game. In one-day cricket, with the extra pressure that having to score runs quickly brings, it forces you to get out of your comfort zone.
"Inexperienced players probably find that harder than coming into a Test match. In one-day cricket there is no substitute for experience."
Meanwhile Sri Lanka captain Mahela Jayawardene was elated by his side's victory at the Rose Bowl, success in their first Twenty20 international achieved without rested senior bowlers Chaminda Vaas and Muttiah Muralitharan.
"Winning is a good habit and under pressure guys performed, which is all positive," said Jayawardene, whose side fought back to draw their Test series in England 1-1 earlier this month.
"It gave us a lot of confidence, especially without Vaas and Murali in the side. It's good because we want to have a squad of players we can take through to the World Cup so, if we have injuries, we have adequate back-up."