The senior signed earlier this year to play at Winthrop University. Then he began preparation for his move to the starting rotation after spending much of last season as the closer.
The left-hander pitched his first complete game of the season Wednesday as the Bulldogs beat county rival Evans 6-2.
Harlem coach Jimmie Lewis said the performance was the type he was looking for when he promoted Gamblin.
"We were hoping he could go seven (innings) this year, and he proved he could go seven," Lewis said.
Gamblin retired 12 of the first 13 batters, struck out five and mixed a high-80s fastball with a curve he worked on in the off-season.
The Knights tried to limit Gamblin's impact at the plate. After driving in a run with a third-inning double, he was intentionally walked his last two trips.
Gamblin's free pass in the fifth loaded the bases for Derek Clayton, who singled up the middle to score two. Harlem junior Jay Aplin's single two batters later also drove in two.
"They just hit the ball with people on base," Evans coach Ricky Beale said.
Harlem is off to a 2-0 start in Region 3-AAAA after beating Glenn Hills on Monday. Beale's team opened region play by beating Lakeside 5-3 on Monday.
Lewis and Beale both said they expect the region contenders could be in for a tight race throughout the season.
Asked what might separate a team, Beale gave a nod to Gamblin's outing.
"If (Gamblin) can throw like that every night out, that may separate them," he said. "That might put them a notch above everyone else, because he threw a great game tonight."
Michael Farr started for Evans and opened strong, limiting Harlem to two runs through four innings. But the Bulldogs gave him trouble in the fifth and reliever Zack Minter entered with the bases loaded.
Clayton jumped on Minter's first pitch.
"He's come up clutch in every situation he's been in this year," Gamblin said.
Reach Stephen Fastenau at (706) 863-6165 ext. 116 or firstname.lastname@example.org.