Dear Sir,
In addition to Mr. Rathi's opinion, I wish to advise you with an option which can provide an opportunity to him to improve performance provided your management is also willing to allow him time to assess that he stands committed and all pending jobs can be completed also. Alternatively In other situation, you can give extension of probation period for another three months in writing as below:
"Dear Mr. ABC,
This is to inform you that your probation will be over on-----=====. Though you might have put in efforts in learning and doing the assigned jobs to you in normal course yet there exist still gaps in performance which has been OBSERVED as " Unsatisfactory " . The said observations and feedback has been pointed out to you by your HOD from time to time.
Management has therefore, decided to extend your probation period for another three months . Please note that your performance during probation need to meet our performance standards. Therefore you are advised to improve upon in desired areas already discussed in details with time lines otherwise it will not be possible to confirm you as a regular employee.(It will be best thing if you write the job details, areas , time lines, targets here)
We expect that you will take this in right earnest and will pay attention for expected level of improvements in the assignments
for XYZ Ltd,
Authorised signatory.