SANTA CLARA — The most talked about free safety among the 49ers defense is one that isn’t on the 49ers defense: Earl Thomas.

As the 49ers switched their defensive scheme to a single-high free safety this season, they’ve tried to clone Thomas, the Seattle Seahawks’ four-time All-Pro.

The 49ers’ candidates: Jimmie Ward, Jaquiski Tartt and Lorenzo Jerome. Each member of that trio has spent the past six months obsessively studying Thomas’ tendencies.

Ward, actually, has followed Thomas since the 2010 BCS National Championship, when Thomas’ Texas team fell to Alabama.

“I know a great player when I see one,” Ward said during training camp.

Ward was moved from cornerback to free safety this spring as the 49ers’ projected version of Thomas, but a hamstring injury has kept him from fully practicing since June, and Ward’s availability remains in doubt for Sunday’s game in Seattle.

When watching film of Thomas, Ward said: “I’m just looking at his breaks. What does he do when the quarterbacks pump? How fast does he get to the ball? How fast does he close space, that’s the most important part? And does he take advantage when he’s right there to make the tackle and attack the ball.”

Tartt started at free safety in the 49ers’ base defense last Sunday, and after a couple errors, he made an acrobatic interception on the 49ers’ goal line to merit praise.

When watching Thomas, Tartt said: “I’ve pretty much have seen all of his games from 2012 to 2016. His fundamental technique is consistent through the whole game. That’s something you have to maintain playing free safety and he does a great, great job at that.”

Jerome, an undrafted rookie, made his NFL debut Sunday in the 49ers’ dime package, playing 12 snaps.

He said: “Every night I probably take a peak at what Earl Thomas is doing. I learn a tip every time I watch him. He’s a great player, a physical player. His instincts are so fast and he knows the play before it happens.

“I just his read steps, the way he reads the quarterback,” Jerome added. “How fast he is in his twitch. The way he’s in and out of breaks. I try to keep watching that and imitate it on the field in practice.”