Jacobus Albertus Mostert
- Bats Right, Throws Right
- Height 5' 10", Weight 165 lb.
Jacobus Mostert was with South Africa in the 2006 World Junior Championship then pitched for South Africa in the 2008 Final Olympic Qualification Tournament. The 19-year-old right-hander allowed one run in 3 1/3 innings against a South Korean team that posted the best offense of the tournament. He got the start against Mexico, which included two former major leaguers in their lineup; he held them to 3 runs in 5 1/3 innings in a 5-0 loss to Francisco Campos. Mostert walked six but allowed only 3 hits; one of the hits was a homer by Karim Garcia. Mostert's 3.12 ERA in the event was the second-best on South Africa, behind only former AA hurler Barry Armitage. The youngster was on the South African roster for the 2009 World Baseball Classic.
Mostert was South Africa's only hurler to pitch in both of their games in the 2009 World Baseball Classic. He allowed no runs in 1 2/3 innings but gave up 3 hits and 2 walks and allowed two inherited runners to score.