Two prospects in deep systems and with the surname prefix "Mc" are on the move.

Astros No. 10 prospect Lance McCullers has been promoted to Triple-A Fresno while Cubs No. 8 prospect Billy McKinney is moving up to Double-A Tennessee, their respective parent clubs announced Thursday.

#Astros officially promote RHP Lance McCullers, Jr. from AA Corpus Christi to AAA Fresno. - #VoteAstros (@astros) May 14, 2015

McCullers had been nearly untouchable in his first seven starts at Double-A Corpus Christi. Having tossed 29 innings, the 21-year-old right-hander ranked second in the Texas League in both ERA (0.62) and strikeouts (43) and was third with a 0.90 WHIP. His .146 batting average-against was lowest among all eligble Double-A hurlers. That comes after McCullers went 3-6 with a 5.47 ERA, 1.56 WHIP and 115 strikeouts in 97 innings at Class A Advanced Lancaster last season.

The 41st overall pick from the 2012 Draft is known for a plus fastball and curveball that has helped him establish a rate of 10.7 strikeouts per nine innings during his three-plus seasons in the Minors. The heater can reach into the upper-90s, although it usually sits a few mph lower than that, and he usually adds a below-average changeup to keep hitters honest. Some control issues (4.5 career BB/9) have hurt his prospect stock in recent years, but he's been improved in that department so far in 2015, sporting a 3.4 BB/9 through his time with Corpus Christi.

McCullers joins an already loaded Fresno roster that added MLB.com's No. 3 overall prospect and fellow 2012 first-rounder Carlos Correa earlier this week. No. 69 overall prospect Domingo Santana and former top prospect Jon Singleton, who made waves by driving in a Grizzlies record 10 runs Wednesday night, help make the Astros' Triple-A affiliate star-studded.

ROSTER MOVES: OF Billy McKinney & INF Wes Darvill have been transferred to the Smokies from @Pelicanbaseball. - Tennessee Smokies (@smokiesbaseball) May 14, 2015

As hot as McCullers was on the mound in Texas, McKinney was equally so for the Cubs' Carolina League affiliate in Myrtle Beach.

The 20-year-old left-handed-hitting outfielder led the Carolina League in all three slash line categories (.340/.432/.544) and ranked second in RBIs (25) through 29 games with the Pelicans at the time of his promotion. He walked (17) more than he struck out (13) and added four homers, two triples and five doubles for good measure.

McKinney came to the Cubs, along with Addison Russell, last July in the deal that sent Jeff Samardzija to the A's. The 24th overall pick in the 2013 Draft played both left and right field for Myrtle Beach and should provide offensive help to a lineup that already includes Cubs prospects Kyle Schwarber, Albert Almora and Dan Vogelbach.

According to a tweet by The Smokies Radio Network, McKinney will become the youngest position player in the Southern League and second-youngest player overall behind Birmingham pitcher Tyler Danish, who is only 20 days younger.