The San Francisco 49ers are just over a month from their first practice of 2015 training camp. Once camp gets going, there will be daily media reports leading up to the preseason opener on August 15. That time will give us a better grasp on the depth chart, and which players have climbed onto the bubble.

As we approach training camp, we'll be assessing the roster in several ways. We'll start with this bubble watch post. We'll go position-by-position, and break down whether players are locks, strong bubble, weak bubble and longshots. The discussion for each article will not follow a specific format, but rather will focus on the more interesting aspects of the particular roster competition. In July, we'll follow this with a look at contract numbers for each position, and we'll close with a look at key questions facing each position.

Locks: NaVorro Bowman, Michael Wilhoite

Strong Bubble: Philip Wheeler, Nick Moody, Nick Bellore

Weak Bubble: Desmond Bishop, Shayne Skov

Longshots: None

My how quickly things change. Six months ago, the 49ers had Patrick Willis and Chris Borland alongside NaVorro Bowman and Michael Wilhoite, setting the team up with one of the deepest inside linebacker units in recent memory. Willis and Borland have since retired, leaving the group with some questions. We don't know how Bowman's knee will respond once he gets back into action, and the rest of the group includes youth and journeymen, but also some solid options.

Bowman and Wilhoite are expected to be the starters when Week 1 arrives. After that, we have some hints about the depth chart, but a few questions as well. Philip Wheeler seems almost certain to make the roster, but when you have a Week 1 roster bonus on a 1-year deal, you are not a sure thing.

I think Wheeler opens the year as the primary backup at inside linebacker, but Nick Moody's development could factor into that as well. Moody has spent most of his 49ers career working with the various special teams units, but he got some time at inside linebacker this past season after Chris Borland went on injured reserve. He struggled in limited appearances, but he has the athleticism to potentially develop into a capable backup. He transitioned from safety to linebacker in college, so he is likely still learning a lot of the nuances of the position. If he can pick things up a bit quicker, he could give Wheeler a run for his money.

I view Nick Bellore as a strong roster candidate just based on his special teams skills. However, he also could end up off the roster at the end of training camp, and back on when the team gets through Week 1. He's younger so it is possible the team won't risk losing him, but I could see it being an option.

Desmond Bishop strikes me as having the better chance at a roster spot than Shayne Skov, primarily because Skov has practice squad eligibility. Bishop brings special teams skills, so if he can flash that, it could be enough to nudge him past one of the many special teams-specific players on the roster.