"He was manipulated by Charles Widmore into going on the race..."
How so?
This is quoted from LostPedia, a pretty trustworthy site.
"Charles Widmore's Sailing RaceLearning that Penny had moved and changed her phone number, he met with Charles Widmore in London to get new contact information for her. Charles relented, giving Desmond Penny's address, confident that Penny would reject Desmond once and for all. Desmond took 2 days leave from the Royal Scots to visit Penny, explaining to her that he needed her new phone number but that he wouldn't call her for eight years. Confused and upset, Penny reluctantly gave Desmond the number. Desmond left Penny's house to return to the Royal Scots smiling contentedly, knowing that in the future he will have made a connection with her, saving his life. ("The Constant")
Desmond managed to reach the rank of a lance-corporal before being dishonorably discharged and serving time in the Southway Garrison military prison for failing to "follow orders". His exact offense is still unknown. At his release, Desmond reclaimed his belongings, including his copy of Charles Dickens's Our Mutual Friend; the book he chose to be the last thing he read before he died, and thus did not check it in prison, to "avoid temptation." ("Live Together, Die Alone, Part 1")
While he was in the Army, Desmond did a six-month detail disarming munitions, a skill he would later have to put into use on the freighter. ("There's No Place Like Home, Part 2")
Outside the Garrison, Charles Widmore waited for Desmond's release. Widmore revealed that he had intercepted all of the letters Desmond had sent to Penelope from prison. Widmore then attempted to bribe Desmond into keeping away from his daughter. Widmore felt certain Desmond would agree to the arrangement, since he believed Desmond to be a coward. Desmond, however, declined, and entered himself in a world sailing race sponsored by Widmore in order to prove his worth. ("Live Together, Die Alone, Part 1")
Desmond then traveled to America, where the race was set to begin. He arrived, however, short of money and a sailboat. Desmond met Libby Smith in a café, where she insisted on buying him coffee. During their conversation, Desmond confided in her his shortcomings for joining the race. Libby then surprisingly revealed her ownership of a boat, the Elizabeth, which had belonged to her late husband "David". Upon her insistence, Desmond eventually accepted Libby's offer of the boat, promising to win the race "for love." ("Live Together, Die Alone, Part 1") "
Perhaps not directly but certainly opportunistic and somewhat manipulative. And if we know anything about LOST at this point, everything is connected...
Al fueled by love, on Desmond's behalf. He is certainly one of the good guys.
