The Arizona Republic reports that the Diamondbacks have fired skipper A.J. Hinch and GM Josh Byrnes.

Multiple sources say the relationship between Byrnes and Derrick Hall, the Diamondbacks President and CEO, was strained.

The club has called a news conference for 10 a.m. Friday at Chase Field.

“These decisions come as a first and major step in our thorough evaluation of our team,” Hall said in a statement. “We have all been disappointed in the results over the last few years, and we have come to the conclusion that a change in the leadership of our baseball operations staff is necessary at this time. This franchise has enjoyed tremendous success over the years, and we want to get back to our winning ways. The loyal staff of this organization, as well as all of our fans, hopes for and deserves better results on the field.”

The Diamondbacks went 349-378 in Byrnes’ nearly 4 1/2 seasons running the club’s baseball operations department.

Hinch, who was promoted controversially from farm director to manager in May 2009 despite not having any coaching experience, went 89-123.

Not a total shock. The D-Backs have sunk to the bottom of the NL West with not much hope of turning things around. Injuries to the pitching staff have been an issue, but the club’s young offensive talent hasn’t developed either. While that’s not always the manager’s fault, he’s usually the way that gets the hook in the end.

The Diamondbacks fired former 2007 Manger of the Year Bob Melvin and are expected to replace him with A.J. Hinch, who is the club’s vice president of player development.

The 47-year-old Melvin’s firing comes after a disappointing start by the Diamondbacks, who entered Thursday 8½ games behind the Los Angeles Dodgers in the NL West. Melvin, who went 337-340 in four-plus seasons, had one year left on a contract he received after being the 2007 NL Manager of the Year.

Melvin’s stock rose when he guided a youthful but talented group to the NL West title two years ago. He was dismissed because many of the same players have failed to live up to expectations based on that season, when the Diamondbacks posted an NL-best 90-72 record despite being outscored by 20 runs across the season.

Speculation about Melvin’s future grew with every 1-2-3 inning by the Diamondbacks’ hitters. Arizona entered Thursday with a .225 batting average, by far the worst in baseball.

Arizona’s offense was a major question mark coming into the season, but as long as the pitching came through the D’Backs were expected to compete in a weak NL West. But Brandon Webb’s shoulder injury (and subsequent trip to the DL) was a crushing blow to the club’s starting pitching and the offense has been even worse than expected.

Melvin can’t do anything about Webb’s injury, Conor Jackson hitting .191 or Eric Byrnes averaging a paltry .139. But the reason he was inevitably fired is because the club has lost all emotion. It’s only May and the D’Backs are playing like it’s August and they’re 15 games out of first. Maybe the 34-year old Hinch can breathe some life into a club that certainly has talent, but is currently lacking any kind of desire.