Seamer James Harris will make his first Glamorgan appearance of the season in the County Championship clash against Leicestershire starting on Tuesday.
Harris missed the opening seven Championship clashes with a groin injury.
Batsman Stewart Walters also returns after missing the defeat to Hampshire because of personal reasons.
And Huw Waters is back in the Welsh county's squad after being ruled out for Hampshire because of illness.
T20 signing Martin van Jaarsveld arrives this week and could play in the county's CB40 match against Surrey on Saturday and the Durham Dynamos (11 June).
He will also be available for selection in Glamorgan's LV County Championship match against Yorkshire at Colwyn Bay (6t-10 June).
"Martin is an experienced, quality cricketer and his record speaks for itself," said Matthew Mott, Glamorgan's head of elite performance.
"We have been looking for genuine match winners to make us a more potent force and off the back of a very successful season in South Africa with the Titans, Martin fits the bill."
Glamorgan squad: G Rees, W Bragg, S Walters, M North, B Wright, J Allenby, M Wallace (capt), J Harris, D Cosker, J Glover, H Waters, W Owen.