In August 2020, Sporting News reported that Saab had sought an early release from his contract due to the traveling distance between Wollongong and his home in Western Sydney. However, St. George Illawarra refused this request unless the club would be compensated either by cash or player transfer.[9] In September, there was speculation that Saab would be joining the Manly-Warringah Sea Eagles as a trade for St. George junior Reuben Garrick.[10]
Saab made only four appearances for St. George in the 2020 NRL season as the club finished 13th on the table.[11]
On 26 November 2020, Saab was granted a release from his contract with St. George and shortly thereafter signed a three-year deal with Manly-Warringah.[12]
2021
In round 1 of the 2021 NRL season, Saab made his debut for Manly-Warringah in the club's 46–4 loss against the Sydney Roosters.[13]
In round 6 of the 2021 NRL season, he scored two tries in Manly's 36–0 victory over the Gold Coast.[14]
In round 10 of the 2021 NRL season, Saab scored another two tries for Manly-Warringah in a 50–6 victory over Brisbane at Suncorp Stadium.[16]
In round 15, Saab scored two tries for Manly in a 56–24 victory over the Gold Coast.[17]
The following week, he scored a hat-trick in Manly's 66–0 victory over Canterbury.[18]
In round 20, Saab scored two tries for Manly in their 40–22 victory over rivals Cronulla in the battle of the beaches match.[19]
At the end of year club awards night, Jason Saab and Josh Schuster were announced as joint winners of the Ken Arthurson Rising Star Award for 2021 after their strong seasons for Manly.[20]
In round 6 of the 2023 NRL season, Saab made his return to the Manly side in their 44–12 loss against Penrith with Saab scoring a second half try.[24]
In round 25, Saab scored a hat-trick in Manly's 29–22 loss against the New Zealand Warriors.[25]
In round 27, Saab scored two tries in Manly's 54–12 victory over the Wooden Spoon side Wests Tigers.[26]
Saab played 19 matches for Manly in the 2023 NRL season and scored 14 tries as the club finished 12th on the table and missed the finals.[27]
2024
Saab played for Manly in the opening game of the 2024 NRL season against South Sydney at the Allegiant Stadium in Las Vegas, Nevada as part of the NRL in Las Vegas opener for the 2024 season. He scored a long range intercept try before halftime, but near the end of the game suffered a hamstring injury that would ultimately see him miss the next 5 weeks. A caption shown on the television broadcast of the game said that Saab, long believed to be one of the quickest players in the NRL (if not the quickest), had a fastest recorded time of 10.67 for the 100 metre sprint.[28]
On 4 June 2024, Saab re-signed with Manly until the end of the 2029 season.[29]
In round 18 of the 2024 NRL season, Saab scored a hat-trick in Manly's 21-20 golden point extra-time victory over North Queensland.[30]
Saab played 17 matches for Manly in the 2024 NRL season and scored 12 tries as they finished 7th on the table and qualified for the finals. Manly would be eliminated in the second week of the finals by the Sydney Roosters.[31]