Reyes, after his impressive showing with the Cardinals down the stretch last season, has seized the top spot from Giolito, who falls to No. 3 behind Glasnow. All three logged meaningful innings in the big leagues last year, as did three other members of the list: Jose De Leon, Jeff Hoffman and Reynaldo Lopez.
Meanwhile, three of baseball's top righties belong to the White Sox, who acquired Michael Kopech from the Red Sox and then Giolito and Lopez from the Nationals on back-to-back days during the Winter Meetings.
1. Alex Reyes, Cardinals
An X-factor for the Cardinals after debuting in early August, Reyes posted a 0.52 ERA out of the bullpen and a 2.20 ERA as a starter, with 52 strikeouts in 46 innings. In addition to his upper-90s mph fastball and plus curveball, Reyes showed improved feel for his changeup against big league hitters and generally was difficult to barrel when around the plate. He should miss even more bats once his control and command improve, giving him the chance to pitch at the front of the Cards' rotation for years to come.
2. Tyler Glasnow, Pirates
Glasnow's dominance in Triple-A didn't translate in the big leagues as Pittsburgh hoped following his arrival in early July, as the 6-foot-8 righty's attempt to pound the zone undercut the effectiveness of his stuff. When he's at his best, Glasnow will both miss bats and generate lots of weak contact with his mid-to-upper-90s fastball, pairing it with a plus curveball and an average changeup.
3. Lucas Giolito, White Sox
The prized right-hander of last year's class, Giolito saw his stock wane over the course of the season and especially in the big leagues, where apparent mechanical issues resulted in diminished velocity and hindered his control. He's shown the ceiling of an ace in the past, with the ability to command a mid-to-upper-90s heater, a knee-buckling curveball and a fading changeup, and now has renowned pitching coach Don Cooper on his side after joining the White Sox as part of the offseason Adam Eaton blockbuster deal.
4. Michael Kopech, White Sox
Kopech began the year on the disabled list with a broken hand, but he made up for the time lost with dazzling performances in the Class A Advanced Carolina League and, later, in the Arizona Fall League. Acquired in the Chris Sale trade in December, the 20-year-old hits triple digits with ease and backs it up with a plus slider and a promising changeup. As he continues to make developmental strides, Kopech will move quickly in 2017.
5. Francis Martes, Astros
Martes overcame early season struggles in Double-A to post a 2.52 ERA over his final 19 starts, and then stood out as one of the top hurlers in the Fall League. With a mid-to-upper-90s heater, a well-above-average curveball as well as a slider and changeup that show average potential, the 21-year-old has the power stuff to ascend to the front of Houston's rotation.
6. Anderson Espinoza, Padres
Espinoza moves up four spots from last year's list after a first full season in which he was traded from Boston to San Diego for Drew Pomeranz during the All-Star break. Espinoza, who will be only 19 years old for the 2017 season, pitches bigger than his slight frame, sitting at 94-97 mph with his fastball and complementing it with a plus changeup and above-average breaking ball. He also has command that belies his age, giving him one of the highest ceilings among hurlers on this list.
7. Brent Honeywell, Rays
Honeywell was a model of consistency last season as he posted a 2.41 ERA at Class A Advanced Charlotte followed by a 2.28 ERA at Double-A Montgomery, while making 10 starts at each stop. The 21-year-old was equally impressive during his time in the Fall League, where he showed a vastly improved cutter along with a plus fastball and his trademark screwball. Honeywell also throws an above-average changeup and a curveball, and he demonstrates plus control of his entire arsenal.
8. Jose De Leon, Dodgers
Pacific Coast League hitters were no match for De Leon last season, as he posted a 2.61 ERA with 111 strikeouts in 86 1/3 innings en route to a Major League debut with the Dodgers on Sept. 4. Allowing five homers in 17 big league innings skewed his numbers, but De Leon, 24, showed he could miss barrels with his plus fastball-changeup pairing while mixing in an average slider. Though he projects for plus control, De Leon will need to be more efficient at the highest level.
9. Jeff Hoffman, Rockies
With four offerings that grade as average or better, Hoffman's stuff is far superior than his 31 1/3-inning big league audition indicates. His fastball and curveball are both plus, his slider and changeup are above-average offerings, and, during Hoffman's time in the Minors, he generally had good control. Hoffman still has a No. 2-starter ceiling, but he'll need to throw quality strikes and miss more bats in order to achieve it.
10. Reynaldo Lopez, White Sox
Overshadowed by Giolito headed into last season, Lopez proved the more effective of the duo in the big leagues before joining him in the offseason trade to Chicago. A more consistent and linear delivery resulted in improved strike-throwing ability for the 23-year-old righty, who can miss bats with his well-above-average fastball, excellent curve and improved changeup.
After missing much of 2015 with a forearm strain, Mitch Keller saw his prospect stock skyrocket last season as he earned Most Outstanding Pitcher honors in the Class A South Atlantic League before making two eye-opening postseason starts for the Florida State League champion Bradenton Marauders. A second-round Draft pick in 2014, he has the makings of three average-or-better pitches, including a heavy mid-90s fastball and a swing-and-miss curveball, with control to boot.
Yadier Alvarez drew raves from scouts during his U.S. debut with his effortless triple-digit velocity, three secondary pitches and knack for missing bats. Signed for $16 million during the 2015-16 international period, the Cuban right-hander averaged 12.3 strikeouts per nine innings across two levels and notched 55 punchouts over 39 1/3 innings in the Midwest League. With much projection remaining in his wiry 6-foot-3 frame, Alvarez could move closer to the top of this list next year.
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.