There is tension between two prominent figures in the Houston Astros organization.

Jeff Luhnow and Bo Porter are at odds, according to Major League sources.

Porter is believed to have expressed his frustration with Luhnow to owner Jim Crane in a conversation earlier this month.

The manager's frustration stems from a lack of input and from his belief that Luhnow engages in excessive second-guessing of his in-game management, sources said.

The Astros hired Luhnow in December 2011 and Porter in September 2012. The lengths of their respective contracts are not known.