The San Francisco 49ers have a lot of holes to fill on their roster this offseason. Steve Wyche of NFL Network believes the defense can be improved immensely by the signing of a single player — safety Earl Thomas.

Thomas will be in high-demand when player agents can begin negotiating with teams on Monday. Two days later, the All-Pro safety can sign with the team of his choosing.

Wyche joined Damon Bruce and Ray Ratto on 95.7 The Game on Wednesday and shared why he believes the signing of Thomas might transform the 49ers defense.

"The Niners play the same system as the Seattle Seahawks do," Wyche said. "He is a game-changing type of player. Now they've got DeForest Buckner up there. He's a stud. Best player in the NFL no one talks about. I like what Arik Armstead did when they moved him inside last year.

"They want to get a pass rusher. That's probably where they're going in the draft. So while they're still developing that front, you get a game changer like Earl Thomas at safety in there, and he will help cover up some of the evolution of what's going on with that front four."

Wyche also believes the 49ers should look at players like Baltimore Ravens linebacker C.J. Mosley, saying he can cover, run, and make impactful plays.

"I've spoken to people up there," Wych continued. "Defense is where they really want to address. I still think they need to get a playmaker at wide receiver. There's not many out there in free agency, so you kind of have to weight what you want to do there. But Earl Thomas would be the guy I would go after immediately."

You can listen to the entire conversation with Wyche below. It begins at the 22-minute mark.