The Philadelphia Phillies' search for a viable fifth starter has another candidate.

Matt Gelb of The Athletic reported that the Phillies are set to promote pitcher Brian Keller to either start or work as a bulk reliever on Saturday. The 32-year-old will be making his major league debut once he appears in a game.

Keller had an interesting road to his debut. Originally a 39th-round draft pick by the Yankees in 2016, Keller spent six years in the Yankees organization before joining the Red Sox as a minor league free agent in 2022. 

He signed with the NPB Hanshin Tigers ahead of the 2023 season, but Tommy John surgery and a second procedure on a nerve in the same area, led to Keller throwing only 15.2 innings over three years.

Brian Keller could stick with Philadelphia Phillies with strong showing

While Keller's velocity returned after his second procedure, he struggled to bounce back from throwing sessions. He had numerous injections and a stem cell transplant as he tried to work his way back, with Keller saying that he was essentially starting over as a pitcher.

Although little was expected after Keller signed a minor league contract with the Phillies in May, he has impressed at Triple-A this season. He has posted a 2.23 ERA and a 1.018 WHIP over his 36.1 innings in Lehigh Valley, striking out 38 batters with 11 walks to get his long-awaited opportunity.

A strong showing could mean that Keller remains with the Phillies beyond this appearance. The Phillies have struggled to find a reliable fifth starter as they have a 5-20 record in games started by anyone aside from Zack Wheeler, Cristopher Sanchez, Jesus Luzardo or Aaron Nola. The rotation could be an area the Phillies look to upgrade ahead of the Aug. 3 trade deadline, but Keller has a chance to seize that spot in the rotation.