However, he said NSW would benefit from having the experienced Thorpe in the squad, especially after Steve and Mark Waugh, Michael Slater and Michael Bevan departed before last season.
Thorpe had announced on Wednesday he had agreed to a contract with NSW, but is not scheduled to arrive in Australia until January, meaning he would be available for the tour to Pakistan but out of contention for England's post-Christmas tour of India.
Thorpe, 36 in August, said he was interested in a coaching role with a Sydney club team in the 2005-06 season and Bayliss said NSW had jumped at the chance to enlist the rising 99-Test veteran as an "insurance policy."
"It basically just started off with Graham wanting to come out and play some grade (club) cricket and be involved in some coaching and have a look at our set-up, just with a view to his future in the coaching world," Bayliss said on Thursday.
"It was a perfect opportunity, if he was going to be out here and wanting to play grade cricket, that we could take advantage of that.
"We wondered if he would be interested in being available for NSW if we needed him. This was very much a one-off.
"He's fully aware that if our batters are doing the job, there's no spot for him. He's happy with that.
"We hope he doesn't get to play for us. He's not coming over to definitely play and take some local guy's place."
Thorpe, who will earn his 99th cap for England in the first Test against Bangladesh starting at Lord's Thursday, is set to become the first overseas player to play domestic cricket in Australia since England's Ian Botham in 1987-88.
Thorpe, who made a hundred on debut against Australia at Trent Bridge in 1993, has scored 6,636 Test runs at an average of 43.94 with 16 hundreds and a best of 200 not out against New Zealand at Christchurch in 2001-02.