England's Adil Rashid said he "couldn't lift his bowling arm" before this summer's World Cup and has still not fully recovered from a shoulder injury.
Leg-spinner Rashid, 31, was given a steroid injection and played in 11 tournament matches, including the final, before ending his season early in August.
"I had an injection just to get me through," he told BBC Radio 5 Live.
"I've been recovering for two and half months now - I'm still getting rehab."
The Yorkshire player is with the England squad in New Zealand preparing for a five-match T20 series. He took two wickets in the six-wicket win over a New Zealand XI on Sunday, but has been rested for the second warm-up match in Lincoln which begins at midnight GMT on Tuesday.
Rashid added: "Hopefully my shoulder will get stronger and stronger during the series.
"We're building to the T20 World Cup in Australia next year. Our first objective is the series here; hopefully we'll come away victorious and then move on."
England will also play two Tests against the World Cup runners-up.