The abrupt resignation of Intel CEO Brian Krzanich has created what could be the first succession crisis in the company's history.

Why it matters: Intel has typically groomed and then promoted one of its own longtime leaders. But the combination of Krzanich's sudden departure and a number of high-level executive exits in recent years has left the company with a surprisingly slim bench.

Though not perhaps the dominant force it was during the heyday of the PC, Intel remains the largest U.S. semiconductor company and a foundational institution in Silicon Valley.

The bottom line: Intel could end up with its first outside CEO, or at least the return of a former executive rather than the promotion of a current leader.

Here's a list of early possibilities, according to current and former Intel employees, as well as chip industry experts.

Internal candidates:

Navin Shenoy, VP of Intel's data center group. He's the most likely of the Intel lifers, but he's also seen as having less experience than the company would normally like.

Murthy Renduchintala, president of Intel's Technology, Systems Architecture & Client Group. He's an insider, yes, but not an Intel lifer, having come over from Qualcomm in 2015.

External candidates with Intel ties:

Renee James, Intel's former president, left the company in 2015 and is CEO of her own server chip startup, Ampere.

Stacy Smith retired in January as group president of manufacturing, sale and operations after 30 years at the company.

Diane Bryant, who ran Intel's data center group until 2015, is currently COO of Google's cloud unit.