Lamb first met Dickerson through his sister, Megan, who met Dickerson in a support group she was in after battling leukemia.
"They became best friends," Lamb said. "He was over at the house all the time. He was also a baseball player, so we became close."
Dickerson, who was a few years younger than Lamb, attended O'Dea High School in the Seattle area, while Lamb attended rival Bishop Blanchet High School. That didn't stop Lamb from doing what he could to tutor Dickerson on the baseball field.
"He was honestly really good," Lamb said. "He was undersized -- a second baseman/shortstop -- but he could pick it and he could hit. He was always asking me questions and I would try to give him pointers."
Dickerson was first diagnosed with rhabdomyosarcoma, a cancer in the soft tissue in the wisdom teeth, in 2009 and had to go through nearly a year of chemotherapy.
"I remember he had Band-Aids on his face and was bald from the chemo," Lamb said.
When Lamb was a junior at the University of Washington and Dickerson was a senior at O'Dea, the cancer returned after a period of remission.
There was no cure, and while another round of chemotherapy might have prolonged his life, if he had done that he wouldn't have been able to play baseball his senior year.
"He was getting letters from colleges when his cancer came back," Lamb said. "He decided not to go through chemo. He wanted to have fun, play baseball and just enjoyed his final year of baseball. He just wanted to enjoy life. In his final game, he had two or three hits and he was just months from dying."
When Dickerson passed away in July 2012, Lamb was playing for the D-backs' Rookie-level team in Missoula, Mont.
Those were not easy days for Lamb, who took four days away from playing to return home for Dickerson's funeral. While he was there, he went with his father to visit his grandfather, who was in the final stages of life.
The day he got back to Missoula, he was biking to the park when his dad called with the news that his grandfather had died.
Lamb remains close with Dickerson's parents, who spend Christmas Eve and Christmas morning with the Lambs.
The way Dickerson approached baseball is something that both drives and comforts Lamb these days.
"So this helps me," Lamb said while tugging on the wristband. "Baseball is a tough game and it is extremely humbling. We go through ups and downs, and any time I'm showing up to the yard with a bad attitude or I'm having a tough game, I just take a glance down at this and remember that he played for the love of the game.
"He was playing when he was months away from dying. So it helps me realize that I don't have it bad at all. It makes me think, 'What would Josh do right now?' I think he'd have a smile on his face, he'd be playing for fun and enjoying his teammates."