Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
The 30-year-old has made 426 appearances for the club over two spells.
Hammell told MFCTV: "I am absolutely delighted to have signed.
"It dragged on a little longer than I would have wanted but I can now look forward to next season.
"The Champions League is probably the best achievement I have managed in my time at Fir Park and we are all looking forward to it.
"Hopefully we can get the rest of the boys signed up, keep this squad together, and go on to have another excellent campaign."Motherwell also offered two-year contracts to defender Tim Clancy and midfielders Keith Lasley and Steve Jennings, while second-choice goalkeeper Lee Hollis is considering the offer of a one-year contract.
Hammell hopes Motherwell can build on last season's third-placed finish in the Clydesdale Bank Premier League but revealed signing on again was a formality anyway.
"I can't really see myself playing anywhere else," said Hammell, who could be in line for a testimonial.
"There were other things out there but all the Champions League stuff and how well we have done recently doesn't really come into my thinking.
"I believe this is where I should be playing.
"There was never any danger of me going anywhere else.
"I still feel I have got a good number of years left in me and hopefully enjoyable ones as well.
"Hopefully I'll be the first of a few who will decide to stay.
"We have had such a good season, if we keep the backbone of that squad and hopefully add one or two, I'm sure we'll have a strong season again."