The A's top three prospects virtually are set in stone. Wherever you look, you likely will see the same three names in the same order: Jesus Luzardo, A.J. Puk and Sean Murphy.

That's a pretty talented trio right there. It's the same top three that led off Baseball America's list of top A's prospects going into the 2019 season. The same goes for 2020.

Luzardo and Puk are regarded as two of the best left-handed pitching prospects in all of baseball. With a high-90s fastball and nasty changeup, Luzardo has all the ingredients to one day be a perennial Cy Young candidate. Puk's fastball-slider combination has him right up there with Luzardo, too.

Murphy is expected to make a big impact on the A's this upcoming season, and the catcher is regarded as one of the best defensive prospects in the game. The 25-year-old made his MLB debut last year and hit four homers in limited time, too.

The real change for the A's, however, is at No. 4. Going into last season, Baseball America had a Heisman Trophy winner as Oakland's fourth-best prospect. That's right, we're talking about Arizona Cardinals quarterback Kyle Murray.

While Murray claims he still believes he can play both sports in a calendar year, and the A's still own his baseball rights, it's highly unlikely the elusive QB ever wears an A's jersey. So, who's the A's new No. 4 prospect? Cal product Daulton Jefferies made a huge leap in the rankings.

Jefferies, 24, entered 2019 as the A's No. 18 prospect on Baseball America's top-30 team rankings. The low ranking wasn't due to his talent, though. It was all because of injury risks. Jefferies missed a chunk of his junior year at Cal with a shoulder injury and then had Tommy John surgery in late April 2017.

Prior to the 2019 season, Jefferies had only pitched 20 1/3 innings since being drafted by the A's with the 37th pick overall in 2016. He was healthy last year and showed his potential that always has intrigued front offices. The 6-foot right-hander went 2-2 with a 3.42 ERA and had 93 strikeouts to only five walks in 79 innings pitched between Advanced Class A and Double-A.

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Jefferies is expected to start the season in Triple-A Las Vegas. He throws everything for strikes and sits in the low-to-mid 90s with his fastball. The A's will be safe with his workload, but don't be surprised if the former Cal Bear makes it to Oakland this season.

There's no doubt the A's have one of the best young trios in Luzardo, Puk and Murphy. Don't forget about Daulton, though -- even if he does spell his name wrong.