Shelby Blackstock will graduate from the Pro Mazda Championship Presented by Cooper Tires to Indy Lights Presented by Cooper Tires for the 2015 season.

Blackstock, 24, of Nashville, Tenn., will enter his fourth year with Indianapolis-based Andretti Autosport and will drive the No. 51 entry.

"I am very happy to be back with the Andretti Autosport team for the 2015 Indy Lights season," Blackstock said. "I'm extremely excited to test the new IL-15 and to see if all the great expectations are true. I want to thank Andretti Autosport for giving me the opportunity to be in one of its cars this year. This team is like a second family to me. I hope there is a lot of success to come from a completely fresh season."

Blackstock earned one victory, three pole positions, 13 podiums and 18 top-five finishes in two Pro Mazda seasons.

"Shelby has been with us for some time now and he's put in a lot of hard work to make the step from Pro Mazda to Indy Lights happen," Andretti Autosport COO JF Thormann said. "We are all very excited to keep Shelby in the Andretti Autosport family and look forward to watching his success continue during this new chapter of his career with us."

Joining the two-time Indy Lights championship-winning team, Blackstock marks Andretti's official confirmation of Indy Lights contention for 2015. The upcoming season will see the race debut of the Dallara IL-15 chassis and AER turbocharged engine.