Rams managerSteve McClaren believes tying down the Republic of Ireland intercontinental could be among the the most crucial parts of small business he will do this summer season.
He informed the club's formal website : " It truly is fantastic news for the Football Club that Jeff has signed a new very long - term contract and it is almost certainly a single of the very best signings we will make this summer time.
"When myself and the coaching workers ended up appointed past year we were aware that Jeff was a participant with lots of likely.
" Viewing him initial hand in instruction every single working day and in match conditions also, it is quite obvious he has a lot of attributes.
"He ended last season in incredibly good variety and created a true affect on the side, so we will be looking for specifically the identical from him at the commence of the new year in August."
Hendrick designed 35 appearances previous season and scored 5 occasions as Derby fell agonisingly brief of advertising to the Leading League.