Mujeeb Ur Rahman will return to Middlesex for the whole of the group stage of next season's T20 Blast, and the quarter-final if the club qualifies.
Mujeeb, 18, took seven wickets and conceded 7.23 runs per over in this season's tournament, and will spend most of the summer in England after being drafted by Northern Superchargers for the inaugural season of the Hundred.
Having spent the 2018 season at Hampshire, Mujeeb played ten games for Middlesex last season as the club reached the quarter-finals of the Blast for just the second time since 2008. He was their go-to bowler in the first six overs, and bowled over 60 percent of his overs during the Powerplay.
"I enjoyed my time at Middlesex so much, so I am very pleased to be coming back," Mujeeb said. "The whole team, on and off the field, made me feel very welcome and hopefully we can be successful together next season."
Stuart Law, the club's head coach said: "It's great to have Mujeeb locked in for the Blast again in 2020.
"His ability to bowl economically in the Powerplay is invaluable and he's a great man to have in the dressing room. We look forward to seeing him back at Middlesex next season."
Meanwhile, the club also announced that Eoin Morgan has been awarded a testimonial year for 2020.