The 24-year-old has returned to The Valley after spending the second half of last season on loan with the Seasiders.
Blackpool had an option to make the deal permanent at the end of the campaign for a price believed to be in the region of £500,000, but it’s understood they opted against doing so.
While Kirk impressed during his appearances for Pool, picking up a handful of assists, he only made nine appearances in total.
With a return to Bloomfield Road looking unlikely, it remains to be seen whether Kirk will remain with Charlton or move on elsewhere.
The Addicks have a new manager in charge in former Swindon Town boss Ben Garner, who has promised to produce an exciting brand of possession-based football.
Asked about Kirk’s situation, Charlton owner Thomas Sandgaard told the South London Press: “He was obviously someone we paid a lot of money for last season. We had him out on loan at Blackpool and he did really well, played a lot of minutes up there.
“We’ve seen interest in him. We’ve got to weigh that between the interest we see from some clubs, how we can utilise him in the squad and how he fits into Ben’s philosophy of playing attacking football.
“Charlie is an attacking footballer, so already there he has a big plus.
“We’ll see how it goes.”