SANTA CLARA, Calif. -- Reigning Offensive Player of the Year Christian McCaffrey again has reset the running back market, signing a two-year extension with the San Francisco 49ers averaging $19 million per year, sources told ESPN's Adam Schefter on Tuesday.

McCaffrey will receive an additional $8 million over what he was scheduled to make in 2024 and 2025 while adding $24 million in guarantees. The deal was negotiated by WME Football.

With his new deal agreed upon, McCaffrey was back with the 49ers for the start of the mandatory minicamp Tuesday after skipping the voluntary portion of the team's offseason program.

His new deal will keep him with the 49ers through the 2027 season. Before the reworked deal, McCaffrey had two years remaining on the lucrative extension he signed with the Carolina Panthers in 2020.

But those two seasons had zero remaining guaranteed dollars in base salaries of $11.8 million in 2024 and $12 million in 2025. The extension guarantees all of that and comes with $8 million more for McCaffrey.

The 49ers announced McCaffrey's extension Tuesday but did not disclose financial terms.

"Two years ago, we were ecstatic to welcome Christian McCaffrey to the 49ers," president of football operations and general manager John Lynch said in a statement. "Since his arrival, he's been everything we thought he would be and more. His versatile skillset has been a seamless fit within our offense. His professionalism and work ethic are as exemplary as I've seen since I've been associated with the NFL. We look forward to working with Christian for many years to come."

McCaffrey is coming off a season in which he posted 2,023 yards from scrimmage and 21 total touchdowns. The 49ers acquired McCaffrey from the Panthers at the 2022 trade deadline, sending 2023 second-, third- and fourth-round picks as well as a 2024 fifth-round selection to Carolina for him.

Meanwhile, 49ers receiver Brandon Aiyuk, who is awaiting a long-term contract extension of his own, has not reported to minicamp as of Tuesday morning. He is subject to fines in excess of $104,000 if he doesn't arrive over the next three days.