Despite the definitive nature of the title of this article, there is no one reason other than: because Padres management said it was time. However, given Bud Black's long track record with the San Diego Padres and the current state of the team, I can provide the basics for how and why this firing took place. Many will argue it was long overdue. Many will say he wasn't give a fair shot. Many will see both sides, but after being on the fence for so long will be happy to see a resolution. I think I fall into that 3rd category.
In Black's 8 full seasons as Padres manager, he managed 2 teams with winning records and 6 teams who basically had no shot at the playoffs. Those two seasons speak loudly for some. In both seasons the Padres playoffs odds (as calculated at the time) were very high at some point in September. In 2007, I believe they peaked at around 83% and in 2010 it was well over 90%. In both seasons the team failed to get over the finish line. They were oh-so-close, but couldn't do it. Obviously, since Black survived the offseasons that followed (although with different front offices) he was not (and really shouldn't be) blamed for those collapses. But, he was the man at the helm and has only those two seasons of playoff contention on his resume. When making an evaluation about what to do in the present, that kind of stuff can weigh heavily on those doing the evaluating.
The latest Padres front office to employ Bud Black has high expectations for the team. That does not include just this season, but last season as well. I've heard from several sources that management considered firing Black last season. Reportedly, Black even knew this was the case. Instead, Josh Byrnes got let go and Black was allowed to stay. Still, the confidence level could not have been very high as he was allowed to manage this season with a contract that expires at the end of it. That lame duck status already set up Black as a potential scapegoat.
The Padres spent the offseason trying to address weakness in the roster and building it up to be a more resilient one than in 2014. They created a number of new weakness along the way, but that can be okay as long as the team as a whole got better. My understanding is that Black was very much on board with these types of changes. He wanted more talent and he would figure out how to get them to play together. Perhaps that only served to tighten the noose. Expectations were greater, but the burden of managing these offseason changes was also greater.
Fast forward to June 15, 2015. Today. The team is 1 game under .500. They are coming off their 4th straight series loss to the first place Los Angeles Dodgers. The defense is suspect, one of the team's stars (Matt Kemp) is struggling mightily, the previous vaunted pitching staff has become more of a problem than was expected and many of the manager's in-game strategies have been questions. It's too early to make changes to the roster and it's too late to say the team just needs more time. Time was up. In managment's eyes Black had to go.
There's no smoking gun. There's no one thing that makes Black's firing make sense. It's all of the above. It's the late season collapses of the past, the forgettable other bad teams he's helmed, the increase in expectations, the near firing of last year, the lame duck contract status and the struggles of the current season. Defenders of the skipper are inclined to say "Should that be enough?" After all, nothing about these reasons specifically point the finger at Black being the problem. The only response I have to that is that at some point you need some way to defend the leader of the team with something besides "He's a good guy that people like and respect".