But it was while playing for the Merthyr Tydfil that Morgan's potential was first spotted by Scarlets coach.
Even then they had their work cut out in whipping a good club player into one ready for the rigours of the RaboDirect PRO12. They did that by making Morgan pound a treadmill wearing a snorkel and a weighted vest.
Eighteen kg lighter and a few barnstorming performances for the Scarlets later, and Morgan was involved in an international tug-of-war between England and Wales for his services.
The No.8 opted for England and showed he is completely at home on the international stage , leaving Grewcock to applaud the work done behind the scenes at Parc y Scarlets.
"Ben is one of those players who hasn't come through the system like a lot of modern players do nowadays of coming through academies," he said.
"He has appeared a bit later on and almost come out of the blue but he looks like he is making up for lost time with the start he has made.
"His England career in the No.8 shirt is only just beginning but I fully expect him to be in that jersey for some time and he looks like he is here to stay.
"I thought he was on of England's best performers in the loss to Wales as not only was he good in the tackle but he kept the ball moving forward which is perhaps something England have been missing in the past.
"He is only 23 so he has a lot more to offer down the years and he is still cutting his teeth at the international level, even though if he looked at him without knowing it you would never guess it."
However, fans will only be able to see Morgan in the RaboDirect PRO12 for a limited time after agreeing a deal to join Premiership side Gloucester int he summer.
And Grewcock expects Premiership defences to cower at the sight of a marauding Morgan in the Cherry and White instantly.
"Ben dealt with the pressure and spotlight of playing against Wales fantastically well, deserved his starting spot and didn't disappoint," Grewcock added.
"It looks as though he is on his way to England with Gloucester and the guys down at Kingsholm will be delighted with that coup.
"So the scary thing is that he still has plenty more to offer down the line and Gloucester will be delighted he is will be doing so in a red and white shirt."
Danny Grewcock is an ambassador for SSE Rugby, supporting community rugby clubs in England. Register now on www.sserugby.com to start benefiting from the support and resources on offer, and the chance to win £10,000 of free SSE energy credits for your club
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