Usman Khawaja will join Glamorgan earlier than expected to provide cover for fellow Australia batsman Shaun Marsh.

The 34-year-old Marsh has been called up to the Australia squad for their forthcoming one-day series with England.

That meant that the left-hander missed Glamorgan's final four games in the One-Day Cup.

Khawaja, 31, who has played 33 Tests for Australia, initially signed as the county's second overseas player for the T20 Blast.

But he will now be available for Glamorgan's next three Specsavers County Championship fixtures - the four-day game against Warwickshire at Edgbaston on Saturday, Derbyshire in Swansea and Northamptonshire in Cardiff.

"We have been in negotiation with Cricket Australia and Usman ever since Shaun was called up to the Australian one-day team and we are delighted he will be joining us early as cover," Glamorgan chief executive Hugh Morris said.

"Usman is a very talented cricketer, who has a fantastic Test record, and I'm sure he will do a great job coming in for Shaun and be a positive influence on our young squad."

Khawaja will miss Glamorgan's final Blast group match after being named in the Australia A squad to tour India from August 17.

"We want to congratulate Usman for being selected for the tour of India - it is always a great honour for any player to represent their country," said Morris.

"Usman will still be with us for the majority of the competition and we look forward to seeing him in action in the Blast."

Khawaja averages 42 with the bat in 33 Tests for Australia, while he has played in 18 one-day internationals and nine T20 internationals.

The left-hander has also proven himself to be a destructive batsman in domestic T20 competitions, averaging 32.73 with a strike rate of 126.19.

He will add more white-ball firepower to a Glamorgan side that made the T20 semi-finals last year when beaten by Birmingham.

"From my point of view, it would be great to be able to take them a step further and bring silverware back to Wales," said Khawaja when his signing was announced in April.

"Glamorgan have some fantastic players in their squad and I can't wait to join up with the team and play with Shaun again."

Glamorgan begin their T20 Blast campaign on Friday, July 6 at Hampshire.

The quarter-finals will be played on August 23 to 26, with the semi-finals and final taking place on September 15 at Edgbaston.

Robert Croft's side have had mixed fortunes with the red ball, starting with a win at Gloucestershire and drawing with Middlesex at Lord's before back-to-back losses to Kent by six wickets and Leicestershire by an agonising three runs.

l England have called up Jake Ball as cover for injured seamer Chris Woakes in their Royal London Series squad to face Australia this month.

Woakes joined Ben Stokes on the injury sidelines after suffering a thigh strain in England's victory over Pakistan in the second NatWest Test at Headingley.

Both will be unavailable for this weekend's one-off one-day international against Scotland and the start of the five-match series against Australia.