The Boston Red Sox have a solid starting rotation and plenty of depth, but could benefit from adding another frontline starter. Earlier this month, Craig Breslow indicated the team would only pursue starting pitchers who could pitch in the top half of their rotation.

The Red Sox have both free agency and the trade market at their disposal to improve their starting rotation. While a player like Framber Valdez or Dylan Cease would be great, their price tag may end up restricting the Red Sox in other spots.

Trading for a pitcher could be cheaper, at least financially, and there are plenty of solid options seemingly available. FanSided’s Brian Burrows urged the Red Sox to acquire Mitch Keller from the Pittsburgh Pirates.

Keller is set to make around $17 million next season. He is not cheap, but he may still be cheaper than some free agents. He is under club control for three more seasons, and ESPN’s Jeff Passan suggested he could be moved thanks to how expensive pitchers may be in free agency.

“If a market for him appears because of high free agent prices and excessive trade asks, the Pirates won’t hesitate to move him,” Passan wrote on Nov. 18.

Keller had a 4.19 ERA last season, but he was an All-Star just two seasons ago. He is a workhorse, making 124 starts in the last four seasons. Adding him to the top of the rotation alongside Brayan Bello and Garrett Crochet would be a solid move for the Red Sox.

While Keller can get the job done, adding him would not be as impactful as adding a pitcher like Valdez or Cease. However, opting to go cheaper on rotation additions may allow the Red Sox to keep Alex Bregman and also sign another impact bat.