I don't think he (Gul) is ready to play in the Tests so soon after his knee surgery," Waqar said on Geo Super channel after the fifth and final one-day international on Friday night.
Gul, who had to undergo a knee surgery in May in Australia won a sudden recall to the national team for the last three one-day internationals against Sri Lanka last week after remaining out of the game for nearly eight months.
Gul is presently Pakistan's most experienced pacer with 163 Test wickets and 161 ODI scalps apart from 72 T20 victims.
"I don't think he is ready as yet to play in a test match where you have to bowl 20 to 25 overs in a day. From the way he bowled in the one-dayers, I think he needs more time to make a complete recovery from his knee surgery," Waqar said.
"For a fast bowler, it takes time to have a complete recovery from a knee surgery. I would not risk pushing him early into Test matches. He is still rusty and needs more time to get back full match fitness," Waqar added.
Waqar said he would not have selected Gul for the Test matches.
"I would like to see him going back to Pakistan and playing in more domestic first class matches to regain complete match fitness. The more four day matches he plays he will get better..Right now since his surgery he has just played in one first class match," he added.
The Pakistan team has suffered several setbacks in the pace department due to fitness issues with its main bowlers.
The tall left-arm pacer, Muhammad Irfan is also on the sidelines after injuring his hip during the last T20 match against South Africa in November in the UAE.
The cricket board has said it is sending him to Abu Dhabi to remain with the team and to undergo his rehabliation process to recover from his injury under the supervision of the national team's foreign physio and trainer, Dale Naylor and doctor Faisal.