IBF welterweight champion Errol Spence (23-0, 20 KOs) is still hoping to land a unification with WBA, WBC world champion Keith Thurman (28-0, 22 KOs).

But based on the latest set of circumstances, it may not happen until 2019 or even 2020.

Thurman has been out of the ring since March of 2017, when he decisioned Danny Garcia to unify their two welterweight titles at the Barclays Center in Brooklyn, New York.

After the fight with Garcia, Thurman underwent surgery for an elbow injury, got married and remained on the shelf for the remainder of 2017.

He was scheduled to return to the ring on May 19th, at the Barclays Center.

But before an opponent could be finalized, Thurman withdrew with a hand injury.

In the weeks leading up to his canceled return, Thurman was openly stating in interviews that he wanted a soft comeback to shake off the rust - and had no interest in facing a high caliber opponent.

Spence believes Thurman has lost some of the hunger that led him to two world titles.

"Dude gets injured more than anybody I know. Thurman can fight. He's a good fighter, but it seems that he's losing the hunger a little bit. If you look at Thurman three years ago, the way he was talking - but now the way he's talking is way different. He's talking like an old fighter on the edge of retiring. Maybe he wants to go to wherever his girlfriend or wife's from and live out the rest of his years. I don't know," Spence said.

"But he needs to stop holding the belts up. He needs to fight or vacate - one of the two."

Spence then explained what circumstances may have created Thurman's current state of mind.

"A lot of things changed for Thurman... more money. He just got comfortable... it just happens over time. He accomplished a lot of things. He beat Shawn Porter and Danny Garcia. He's the champion now. A lot of things changed, he's real comfortable now. He's getting a lot of money now, he's not as hungry as he used to be," Spence said.

Thurman already has two mandatory obligations waiting for him when he returns - and both are under the WBC.

He will have to defend his belt against Shawn Porter first, and then Danny Garcia is the next mandatory in line. There is the possibility that the WBC will order Porter and Garcia to fight each other for the interim-title.