Tsotsobe, the 27-year-old nicknamed Lopsy, has been a prolific wicket taker in South Africa\'s one-day side.
London: Essex has signed South Africa pace bowler Lonwabo Tsotsobe as the English county's overseas player for the first part of the season.
The left-arm seamer missed the county championship season opener against Kent on Friday, but he is set to make his debut against Middlesex next week.
Essex head coach Paul Grayson says Tsotsobe "offers variation and we hope he will make a big impact for the start of the season."
When the Twenty20 season begins in June, New Zealand all-rounder Scott Styris will replace Tsotsobe as Essex's overseas player.
Tsotsobe, the 27-year-old nicknamed Lopsy, has been a prolific wicket taker in South Africa's one-day side, but played only once at the recent World Cup because of the Proteas' policy of using an extra spinner.