The San Francisco 49ers are kicking off phase three of the offseason workout program next week, with three weeks of OTAs leading up to a mandatory minicamp to close out the program. Teams cannot get physical in phase three, but they are allowed to run full offense vs. defense drills. They have been working to implement the offensive and defensive playbook, and this allows them to take things a big step further.

Over the next couple months until training camp starts, we’ll be breaking down all the position battles. In the meantime, I thought it would be useful to come up with a list, including what we think are the most important, or at least most interesting competitions. The 49ers are in the midst of an overhaul that will see a lot of new starters. We know some players are clear starters, but most players are competing for either a starting job, or just a rotational role.

Offense

We know the quarterback position is not up for grabs, with Brian Hoyer set to start. We can say with some certainty that Pierre Garçon is going to be the No. 1 receiver. Who is behind him is another question entirely, but there is no question about Garçon. Joe Staley seems like a lock at left tackle, and we know Kyle Juszczyk is going to be in whatever his “offensive weapon” role entails.

Beyond that, there are plenty of questions. Carlos Hyde should be the early favorite at running back, but Joe Williams could give him a run for his money. Williams slipped after leaving and returning to the Utah football team. It was a tough sell for Kyle Shanahan, but he, Williams, and Utah coach Kyle Whittingham convinced Lynch to make the move. I think Hyde is the No. 1 back when Week 1 arrives, but training camp will be interesting.

At wide receiver, Jeremy Kerley is coming off a solid season, but it was on a pretty bad team. The 49ers extended him, signed Marquise Goodwin and Aldrick Robinson, and drafted Trent Taylor. There is a wide open competition for looks after Garçon.

The offensive line is all sorts of a jumble. The 49ers acquired Jeremy Zuttah via trade, and signed Garry Gilliam, Tim Barnes, and Brandon Fusco. They’ll all be competing with C Daniel Kilgore, guard Zane Beadles (and potentially Joshua Garnett), and tackle Trent Brown. I have no idea how that whole group will shake out.

And of course, the tight end position is another mess. The team drafted George Kittle in the fifth round and signed Cole Hikutini as a UDFA, while trying to trade Vance McDonald. I have no idea what to make of this group at this point.

Defense

The change in defense raises all sorts of questions about position competitions. We know Jimmie Ward is the front-runner at free safety. Eric Reid is likely a strong favorite at strong safety, but he could get some competition from Jaquiski Tartt.

At cornerback, Rashard Robinson should be a favorite, but with both starters from 2016 gone, anything is possible. Ahkello Witherspoon has a chance to grab a starting job quickly, but if he is slow to develop, Keith Reaser or Dontae Johnson could secure a starting spot. And of course, the nickel is up for grabs between K’Waun Williams, Will Redmond, and guys like Reaser and Robinson.

At the second level, the linebacker roles are a bit of a hodge podge. It seemed like Ahmad Brooks and Malcolm Smith will start outside, with NaVorro Bowman in the middle. But then the team drafted Reuben Foster in the first round. If he is healthy, who does he potentially replace? One option could be seeing Smith playing weak side on base downs, and then Foster coming on next to Bowman in the nickel. Or does Foster replace one of them full-time?

Up front, there are a lot of questions. The team signed Earl Mitchell and drafted Solomon Thomas, to go along with DeForest Buckner, Arik Armstead, Aaron Lynch, and plenty more. Mitchell and Buckner would seem to be base down interior linemen, with Lynch at Leo, and Armstead and Thomas competing for the other end role. But we could also see a lot of rotation along the line. This could be the most curious competition just because it might be the deepest position on the roster.

What would you say are the top two or three position competitions as OTAs approach?