Acute Lower leg (Calf area) pain during tennis match

Hello,

I am a 57 year old male. I retired just over 12 months ago. 7 months ago I took up playing tennis again and joined a local club. (I used to play on a weekly basis up to my early 40s).

On at least 3 separate occasions now I have picked up an injury to my right lower leg (Calf area), the most recent occurrence being 2 days ago.

The injury is normally caused by me making a sudden lunge - usually to reach a drop shot - and results in a sharp pain in the calf area. I am then unable to continue to play on and walking is also very painful.
On returning home I apply ice and rest and take Ibuprofen.
My first assumption was that I had pulled / sprained / torn part of my calf muscle. However, after 24 hours I find I am able to walk with little pain and after 48 hours with no pain. There is no bruising and no swelling.
After the first occurrence I consulted the local physiotherapist and he diagnosed that there was no muscle damage but I had over-stretched nerve fibres in my leg. These would heal much quicker than a torn muscle and I would be able to resume playing tennis in a week. Which I did.

I have tried to find out more online about this diagnosis but I have been unable to find anything. I don't believe its a muscle injury (eg tennis leg) as the recovery time is so short. (also no swelling or bruising)

I am concerned that this has occurred 3 times now.

Does anyone have any knowledge of this injury and what I can do to prevent recurrences?

Many thanks in advance for your help

Dave