Kittle is entering the final year of his rookie contract.
"I know right now, as we speak, every day, I know John's upstairs working his butt off talking to Kittle's agent, and those two are trying to work it out," Shanahan said.
It doesn't sound like too much progress has been made, according to Silver.
"I talked to Kittle's agent, Jack Bechta, yesterday," Silver told Andrew Siciliano. "He said progress has been minimal, and later reinforced that by texting me an inchworm emoji to underscore that fact. It's not just money. There is structure, and how much money a player like George Kittle could get upfront, how much would actually be guaranteed.
"And at the heart of all this has been somewhat of a philosophical divide between the 49ers, who say, 'Listen, we want to pay you more than any tight end ever because you're the greatest tight end,' and Kittle's camp, which is saying, 'Don't view me as a tight end. I was just voted the seventh-best player in football at any position.'"
Added Silver: "I think this week will be a very, very pivotal week for George Kittle and the 49ers."
Shanahan noted that he is thrilled not to be the one paid to deal with contract negotiations. He, however, knows what Kittle means to the 49ers.
"That's why we're doing everything we can to make sure he's here for a long time," Shanahan added. "Lots of stuff to talk through with that. Stuff that I am very glad I don't get paid to do."