The San Francisco 49ers are reporting to training camp on Wednesday, and that means position competitions will start to come into focus. The team kicks off practice on Thursday, and in advance we wanted to highlight the intriguing storylines heading into San Francisco’s first practice. We discussed offensive storylines earlier today, and now move on to defensive storylines.

10. Will DL Solomon Thomas develop in his second seaon?

The 49ers’ No. 1 selection from last season was underwhelming for where he was drafted, unable to find success as a pass rusher.

Thomas’ development along the defensive line can go a long ways to improving the 49ers’ defense. Thomas, in combination with DLs DeForest Buckner, Arik Armstead and Cassius Marsh could grow into a dominant group.

All eyes should be on the growth of Thomas as a pass rusher and run stopper in his second training camp.

9. Can CB Ahkello Witherspoon accept the challenge?

The ex-Colorado defensive back will be heading into his second season as a 49er with massive expectations on his shoulders. Witherspoon became the starter for SF towards the latter half of last season and didn’t look back.

Robert Saleh and the defensive coaches will count on Witherspoon to be one of the fixed starters — with heavy expectations — heading into training camp, so will he be up for the task?

8. Monitoring Robert Saleh’s growth in Year Two

The first-year defensive coordinator, Robert Saleh, was a pleasant surprise for the 49ers. Many didn’t expect much from him, after Kyle Shanahan hired Saleh late into the offseason with limited options.

Saleh turned around the 49ers’ rushing defense and the youth in the secondary certainly grew under his tutelage. Like Shanahan’s potential offensive growth in Year Two, we’ll have to keep a close eye on what Saleh has under his belt too.

7. How will LB Reuben Foster’s suspension impact the 49ers?

The 49ers’ best player — not most impactful — is LB Reuben Foster. He’s likely going be the second or third-best player at his position by the end of the season, but San Francisco’s going to be missing him for the first two games.

With no Foster, the 49ers are going to lean heavily on their linebacking depth to handle the middle of the field to start the season. Rookie LB Fred Warner, Malcolm Smith and Brock Coyle will have to step in, but can they handle the load?

6. Where is DB Jimmie Ward going to land?

The 49ers’ defender that’s gotten the Alex Smith treatment is Jimmie Ward. Numerous changes in coaching staffs, adjustments from safety to cornerback and injuries have hindered the growth of Ward.

Heading into 2018, DBs coach Jeff Hafley is expecting Ward to compete to be one of the best 11 players on the field, not guaranteeing a spot for him. The likely fit for Ward will likely be as a boundary corner, but will he finally land in a role that works for him and the team?

5. What role will OLB Jeremiah Attaochu play?

The 49ers’ pass rush was bleak in 2017, but there’s some reason for optimism heading into 2018: free-agent Jeremiah Attaochu.

The ex-Charger was stuck behind the likes of DEs Joey Bosa and Melvin Ingram in Los Angeles, but he finally has his chance to shine. The 49ers’ leading pass rusher from last season, Elvis Dumervil, isn’t on the roster any longer.

That’ll give Attaochu a chance to grow into a big pass-rushing role in 2018, a storyline that 49ers’ fans should be enthusiastic about.

4. Following DT Arik Armstead’s comeback from injury

After having his fifth-year option picked up, it’s time for DT Arik Armstead to deliver the goods for the 49ers this season. After suffering an injury and not finishing last season healthy, Armstead will use this training camp to improve on a lot of different fronts.

The ex-Oregon defensive lineman will be transitioning to a new position on the field, playing the Big End, rather than the Leo. Armstead has put on about 15 pounds in the offseason and his health and adjustment to his new role should be closely watched.

3. Which rookie CB is going to emerge from the pack?

John Lynch went defense, defense, defense in the 2018 NFL Draft and we’re about to watch it all pay dividends during training camp.

Robert Saleh and the defense will have cornerback depth unlike last year, especially with a boat load of rookies. The key to watch during the first few weeks of practice is the rookie that’ll separate himself from the rest.

It’ll be someone from the group of D.J. Reed, Emmanuel Moseley, Tarvarus McFadden and Tarvarius Moore. With likely only one or two of those names landing on the 53-man roster, early impressions will count.

2. San Francisco’s growing depth at the safety position

While Trent Baalke was the general manager for the 49ers, a go-to joke was all the safeties he drafted. Yet in 2018, it isn’t a joke anymore, San Francisco is loaded with a bevy of talented safeties.

With Jaquiski Tartt and Adrian Colbert the likely starters, Robert Saleh will also have Chanceller James, Marcell Harris, and potentially Jimmie Ward among others at his disposal this season. It’ll be fascinating to see how the depth develops behind Tartt and Colbert.

1. How will CB Richard Sherman return from injury?

The 49ers’ most important offseason signing wasn’t their most expensive one, it was CB Richard Sherman. Adding veteran savvy, leadership and some stability to the defensive backfield was important this offseason, but how will Sherman come back from injury?

After playing in nine games in 2017, the ex-Seahawks’ CB tore his achilles and has been recovering since. San Francisco is penciling in Sherman to be the starting outside cornerback opposite to sophomore Ahkello Witherspoon, but will he be ready to go?

Based on all the pre-training camp reports, Sherman should be healthy, but it’ll be an important storyline to monitor as we progress into August.