Essex Head Coach Paul Grayson said he was delighted Mahmood had joined the club.
"I like cricketers who feel they have point to prove to people and he has lots of ability, he's experienced and he's a fit guy who can bowl with good pace as well so we feel Saj will be a real addition to the squad."
More top news
Any showers should die away this evening with most places dry overnight.
The veteran rockers Status Quo have been forced to postpone a concert in Norwich this weekend after frontman Francis Rossi became ill
Police are ramping up security at the British Grand Prix at Silverstone this year in the wake of a number of terror attacks.