Why are modern day players out for so long with injuries ?

As the title states , now I,m 51 years old and have watched and loved Celtic through thick and thin, how is it that say a thigh strain, and I,m only taking that injury as an example now takes months to get over when back years ago players were recovered and playing in less than half the time ?
Yes there are more games in today's leagues what with Europe etc, but at the end of the day players seemed to recover or perhaps wanted to recover a lot faster than nowadays.
I,m open to any reasoning.

 

Because they are worth more to the club in the long term. Back in the day players were on short contracts, an asset needs to be managed properly a small injury can get worse if not looked after and cost the club millions on wages with no return. They are insured for millions, modern science can detect injuries that would never have been noticed before. Plus they are all poofs

 

utter fan dans 99% of them , jeezus if one of them sneezes the squad coughs .