"I don't think Umar should be playing in the Test series, he is not ready as yet for the longer version of the sport," Waqar told Geo Super channel.
"I am afraid for him because I think he needs more time and he should have played more domestic cricket before being pushed back into Test cricket."
The 29-year-old Gul underwent knee surgery in Melbourne in May after getting injured during Pakistan's tour to South Africa.
Gul, who is the most experienced fast bowler in the Pakistan team after taking 163 Test, 168 one-day wickets, was recalled for the last three one-dayers and the three-match Test series against Sri Lanka.
Waqar said he would not have selected Gul for the Test matches as it takes fast bowlers more time to get fit following knee surgery.
"I would like to see him being sent back to Pakistan and playing in more domestic first class matches to regain complete match fitness," Waqar added.
The first Test begins in Abu Dhabi on Tuesday.