Glamorgan will be without the services of overseas batsman Herschelle Gibbs for their last four games of the Twenty20 Cup. Gibbs' arrival has been delayed by commitments in South Africa and his place will be taken by Mike O'Shea, who returns after serving a three-week ban imposed for a drink-driving offence.

Glamorgan opted not to retain Australian batsman Mark Cosgrove as their other overseas option because the county has failed to qualify for the quarter-finals. Cosgrove will play Lancashire League cricket and will be available for Glamorgan's second team matches during the week.

"We're desperate to win the matches but we may as well give our youngsters the opportunity," Glamorgan cricket manager Matthew Maynard told BBC Sport. "Mark's contract ended and we had Herschelle to come in but he's had to go back to South Africa for a Cricket South Africa function."

Gibbs, 35, played for the county in the Twenty20 Cup last summer, replacing their outgoing overseas player, Jason Gillespie.

It has been a disappointing tournament for Glamorgan. They have only won one game in six before the Twenty20 Cup was interrupted to accommodate the ICC World Twenty20. "We wish O'Shea and the other youngsters all the best for the tournament," said Maynard. "It gives us the opportunity to juggle a couple of things and use it as an experimentation."