The 35-year-old will make his 737th Reds appearance against QPR on Sunday before moving into television punditry with Sky Sports next season.
However, Werner said the club would welcome back former England international Carragher, who has spent his entire playing career at Anfield, with open arms.
"We wish Jamie well in his new career and the door will always be open for him at Liverpool," he told the Liverpool Echo.
"I really hope we see him back at the club one day because with all that experience and knowledge we know he has so much to offer.
"Whether it's as a coach, an analyst or whatever, there will always be a job for him here.
"We hoped he would play on for another season but we fully respect his decision to retire.
"He wants to leave the party before the last call and I understand that.
"I have nothing but admiration for him - both on and off the field.
"It's a big challenge to try to replace him. He's a unique individual and I think finding another player just like him will be impossible."