According to Sportsnet’s Elliotte Friedman in his regular column “31 Thoughts”, there is a chance that Ryan Kesler might not play in the 2018-2019 season.
In thought number 4 of the column, Friedman notes that Kesler will not have surgery, but will be undertaking an intensive rehab and training regimen to rebuild strength in his hips. So while Kesler is in all likelihood planning to be ready for the start of the season, it appears that the possibility of Kesler taking a year off has been discussed internally.
Friedman notes that Kesler does not plan to retire and wants to get back on the ice as soon as possible.