SANTA CLARA (CBS SF) — Inspiration comes in many shapes and forms for professional athletes. For San Francisco 49ers standout tight end George Kittle, the source is the written word — letters his father’s lovingly writes him before each and every game.

Kittle’s father, Bruce, was a former standout lineman at Iowa. He began penning the letters when George was a sophomore, also playing for the Hawkeyes and they have arrived in time for every game since.

“I got one about 10 pages, it was awesome,” George said of the letter before last week’s playoff showdown with the Minnesota Vikings. “I was fired up and ready to roll. It (last week’s letter) was a little longer. He was on last week. It was pretty fun. It was a great one.”

While not willing to share its contents, it likely reminded George to do all he could to help the 49ers win. George was not a major factor in the passing game, but he displayed his devastating blocking ability on the edge.

For the game, San Francisco ran the ball a stunning 47 times for 186 yards. Of those plays, 26 running plays were outside the left tackle or right tackle with Kittle leading the way.

George said every week the letter takes a different twist or turn.

“It’s awesome whether he’s telling a new story or bringing in a new movie or book that he read to me as a kid,” he said. “He just always has a different story line for every single letter. He always just crushes it. I always get pretty fired up reading those things.”

When asked what advice he gets on his play, George said his father sticks with blocking.

“He doesn’t give me too many tips on how to run routes,” he said with a chuckle. “He always gives me — make sure your leverage is good, get your hands inside. He’s definitely a coach.”

49ers coach Kyle Shanahan appreciates the fatherly advice Kittle receives. It helps shape his star tight end’s unique skill set — punishing blocker, dangerous pass receiver and tough to tackle.

“Kittle, everyone knows what he’s done in the pass game, but he has never once in three years came up to me during a game and said ‘Hey I need this route or Hey we’ve got to do this,'” Shanahan said. “He’s never once came up to me about a pass play, but he comes up to me about every seven plays about what kind of run play we need to do, who we need to allow him to hit, things like that. It makes it very fun to call plays for him.”