Of Carroll's arrival, Jewell said: "It has been a protracted deal but I believe it will be worth the wait because Roy is a great pro and he will come straight into contention for Saturday's game at Birmingham."
It was no surprise to see Jewell make further moves to strengthen a Rams defence which has conceded 51 times in 24 games this season, with Everton defender Stubbs arriving on an 18-month contract.
No fee is involved for the 36-year-old, who has made almost 350 league appearances in England as well as more than 100 in all competitions in Scotland.
Jewell believes Stubbs' experience will be invaluable as the Barclays Premier League's bottom side aim to bridge a 12-point gap to safety.
He added: "It's a terrific 'capture' for us. Stubbsy is a first-class pro - someone who has been there, seen it and done it.
"I'm delighted to have him on board, and he will add experience and steel to the back line.
"He will train with us on Friday and is very much in contention for a place in the team on Saturday."