Krept, one half of Krept and Konan, has cancelled his shows in October after a warning from his doctor.
The pair were due to do seven shows back-to-back in November performing songs from their newest album Revenge is Sweet.
He says he has been "back and forth" from hospital since he was attacked backstage at the BBC's 1Xtra Live event in October.
The rapper says his plans for the tour "require 100% strength".
Krept was "slashed" in a backstage scuffle at the event in Arena Birmingham and treated on site.
Following the assault, the concert was called off early and the headliners didn't get to perform.
West Midlands police told Newsbeat no arrests have been made but investigations are ongoing.
Krept says he made the decision to postpone the tour because he didn't want to "collapse on stage".
He said: "All tickets remain valid of course and I promise it will be worth the wait... health is priority and I'm sorry for any inconvenience."
The show in London's O2 will go ahead as planned in December.
Love Island winner Amber Gill was among those who left supportive comments on the rapper's Instagram post.
Due to perform with Krept and Konan are rappers Yungen and K Trap, as well as Kiico who won BBC Three's The Rap Game UK.
Another contestant from the talent show, Ransom FA, will perform at the duo's Glasgow show.