"If anybody can do it, I think he can," Dr Mansingh told reporters at last Thursday's Sports Club forum at the Jamaica Observer.
Shillingford took six wickets at an average of 42.66 in the first two Test matches against hosts New Zealand, but was not available for the final match in Hamilton which began on Thursday.
A statement issued by the ICC ahead of the third Test said that an independent biomechanical analysis had been done on Shillingford's action.
Cricket's governing body revealed that for Shillingford's standard off-break delivery and for his doosra (ball that turns like a standard leg-break), the amount of elbow extension in his bowling action exceeded the 15 degrees level of tolerance permitted under the ICC regulations.
The Dominican, one of the premier regional spinners over the last few years, will remain suspended until he submits a new analysis that proves his action has been corrected. He is scheduled to return to the Caribbean following the match.
Shillingford was previously suspended in December 2010 and later cleared in June 2011.
He has taken 65 wickets in 14 Test matches at 32.32 since making his debut in June 2010. In 86 first class matches he has 378 victims at 23.62.
Despite his own optimism, Dr Mansingh, a member of the ICC medical panel and a Jamaica Cricket Association (JCA) board director, conceded that a hard road lies ahead for the spinner.
"It's going to be very difficult, because if you realise it's the second time it's happened to him. So he went for remedial action and he came back and it's going to take a lot of effort (to do it again), but he's a mentally strong guy," he said.
The ICC also said that part-time off-spinner Marlon Samuels' bowling action for his quicker delivery, exceeded the 15 degrees limit and therefore, was considered to be illegal.
Samuels, who is more renowned for his stylish batting, is however, allowed to continue to bowl his standard off-break deliveries in international cricket.
If Samuels is reported for a suspect action in the next two years, the ICC will deem it as a second report and he will have to undergo a biomechanical analysis. If it is concluded that Samuels has an illegal action for any delivery, he will be banned from bowling in international cricket for at least 12 months.
Samuels has not bowled in the series thus far.
