3:01 PM ET

One of the top fighters of the past decade has announced his retirement at the age of 33.

MacDonald made the announcement less than 24 hours after he was defeated by Dilano Taylor in the PFL semifinals. MacDonald didn't make an announcement until Sunday morning, after removing his gloves in a symbolic gesture.

MacDonald said his time had come to put the gloves down. I'm thankful for the sport and the people I've met along the way.

MacDonald signed with UFC at the age of 20 after making his MMA debut. He was a new breed of mixed martial artist as he did not come from a traditional background. MacDonald trained full MMA from his first day in combat sports.

MacDonald went 9-2 in his first 11 UFC appearances after training with George St-Pierre. During that time, he defeated some of the best of his era, including: One of the greatest fights in MMA history took place in July of 2015, when he tried and failed to get the UFC title back from Robi.

MacDonald signed a lucrative contract with Bellator MMA. He won the title for the second year in a row. MacDonald had a chance to become a two-weight champion in the following year, but lost via second-round TKO.

MacDonald was a member of the PFL. He was knocked out of the tournament in the semifinals in both of the years.

MacDonald said that he has learned a lot about himself through his career. I've made a lot of mistakes along the way, but I'm 33 years old and a better man because of them.