The San Francisco 49ers' OTAs and the team's mandatory minicamp are well in the books. Training camp looms and - along with preseason - will be the final barometer for coaches to determine team roles on offense and defense prior to the start of the regular season.

The 49ers had a number of losses during the offseason. We've already heard about all of the retirements and free agent losses, which have led the media to predict nearly certain doom for San Francisco's 2015 campaign. Whether they are correct or not is yet to be determined. Sealing the team's fate before even one snap has taken place is a bit premature.

There have indeed been losses to the team, which has forced others into starting roles. The most interesting of those players are those that have never been full-time starters before. They will suddenly become "the guy" at their position and how they perform could make or break the 49ers' season. While this is a tough task for any player, it is an even tougher task for players that don't have a good deal of experience within the league.

Let's take a look at four such players who, barring injury, have the best chances to thrive in their new situations.

Running back Carlos Hyde, who is entering his second year after being selected in the round two of the 2014 NFL Draft, will be taking over the starting role once held by the team's all-time rushing leader, Frank Gore. Much to the dismay of many fans, Gore signed with the Indianapolis Colts as a free agent. This may be the most obvious choice on this list because Hyde has the most playing experience. He was thrust into the backup role in 2014 after Gore's scheduled backup, Kendall Hunter, missed the season with an ACL injury.

For the fourth straight season, Gore had surpassed 1,000 yards rushing. In fact, his 1,106 yards in 2014 was the eighth time in nine years that Gore had surpassed the millennium mark. Last season, he accounted for over 72% of the team's carries by running backs. Hyde accounted for only about 24% so to compare their numbers really isn't fair. What's to say that had Hyde contributed more, that his numbers might have exceeded Gore's? Of course, what's to say that they wouldn't have? We are certainly going to find out this season, but even that comparison will be like apples and oranges due to the amount of change that has taken place.

During his 83 carries in 2014, Hyde averaged exactly 4 yards per rushing attempt in relief of Gore. Gore averaged 4.3. Similar numbers, yet very different runners. The team was frequently using Gore in the middle and restricting his runs to the outside. Hyde on the other hand, proved to be effective in both areas.

Hyde averaged over 9 yards per carry in the team's second matchup against the Seahawks. Although, a 28 yard scamper, his longest run of the season, contributed to much of that inflated number. On the other hand, the Seahawks, who finished the season with the third best run defense in the league, were not known for giving up such long runs. However, in games where Hyde was handed the ball at least 10 times, he averaged only 2.7 yards per carry.

The positive for Hyde is that he will have some help. Kendall Hunter has averaged 4.6 yards per carry throughout his career. In 2012, he averaged 5.2 in 72 attempts. Competing behind him are former USC star Reggie Bush and Australian rugby star turned football player Jarryd Hayne. The team also drafted Mike Davis out of South Carolina in May. Whatever the final roster looks like, putting in some relief for Hyde should not be an issue.

When the 49ers kick off against the Minnesota Vikings on September 14, Hyde will be the starter for the team. One problem for Hyde is that he will be running behind an offensive line that has lost guard Mike Iupati, who signed as a free agent with the Arizona Cardinals, and tackle Anthony Davis, who abruptly retired. While both had their issues in pass protection, they were instrumental in the running game. For example, in the seven games that Davis played in 2014, the 49ers offense averaged 173 rushing yards per game. In the nine games that he missed, they averaged just 107 yards per game.

When Iupati left for NFC West rival Arizona, Brandon Thomas was the natural choice to succeed him. Preparing for Iupati's departure was complete when the 49ers selected the massive Clemson guard in the third-round of the 2014 NFL Draft. Formerly rated by many as a first-round caliber, Thomas was considered a bargain when his stock fell due to an ACL injury that occurred prior to the draft. He was not going to make an immediate impact for anyone, but if a team like the 49ers, who didn't have a pressing need at guard could hold onto him until he recovered, it was believed that he had the potential to solidify the position.

The 49ers were making a habit of selecting injured players in the draft that the team would stash for a year, allowing them to learn and recover. They could do this because of the depth they had at the time. Even now, when depth has become a larger concern, general manager Trent Baalke continued the practice with his selection of wide receiver DeAndre Smelter, who joins their All-ACL team. He, like Thomas, has the potential to be an eventual starter. The gamble did not work on running back Marcus Lattimore, who never fully recovered and retired, but the 49ers hope Thomas' situation is different.

Thomas is not an Iupati clone. Despite his massive size, he is considered to be very athletic, has quick feet, and uses those attributes to win positioning against defenders rather than simply using brute strength to shove them around. This could be a huge asset to anyone running behind him - like Carlos Hyde.

The other key advantage that Thomas has over Iupati is his ability to pass block. Playing some tackle in college gave him the experience needed to learn to move with defenders and keep them from the quarterback. His long arm reach, a trait that has become popular with Baalke selections, will be an additional asset when he attempts to shift defenders' directions and recover if needed.

All of this is assuming that the 49ers don't bring in a free agent to compete along the offensive line. That scenario would give the team more personnel options as they attempt to better protect quarterback Colin Kaepernick and continue to open holes for the running backs. He is definitely someone to be excited about and could shock a number of team critics with his ability to step right in and take over.

Let's shift over to the defensive side of the ball, where defensive end Tank Carradine hopes to be primed to make an impact along the line. Like Hyde, Carradine does have some actual NFL game experience. After spending 2013 fully recovering from an ACL injury that he suffered at Florida State, he appeared in nine games in 2014 where he had 17 tackles and three sacks. The three sacks came within the final three games of the season, which included two against the Seattle Seahawks. With last year's departure of Ray McDonald and this offseason's retirement of Justin Smith, the 2013 second-round selection will look to book-end the line with free agent acquisition Darnell Dockett.

It wasn't until the loss of McDonald that Carradine started to see more playing time in 2014. A lot of that was his self-admitted inability to master the playbook. While some have criticized his play, his explosiveness at the line during the end of the season made others believe that he could be a solid pass rusher in the future.

Of course, it is possible that the team could see Carradine and Dockett as players to bring in on passing downs, and allow them to split time with others like Quinton Dial and Glenn Dorsey. Especially if Dockett, who missed all of last season due to an ACL tear, misses significant practice time prior to the start of the season. He has yet to practice with the 49ers. Dial impressed during minicamp and played with the first-team. He looks primed to move to end after filling in at tackle last season. Dorsey may play at end as well because Ian Williams is penciled to start at nose tackle for the team. It is a position that Dorsey is familiar with due to his time with the Kansas City Chiefs.

The defensive line will begin to take shape once training camp begins and better evaluations can be made. It should have some pretty interesting training camp battles. The team also spent their 2015 first-round selection on Arik Armstead, who also hasn't practiced with the team yet due to NFL rules regarding school obligations.

Last but not least is the team's fifth-round selection in this year's draft, Bradley Pinion, the punter out of Clemson. How much confidence does the team have in the rookie? Enough to ship the team's longest tenured player and Pro Bowler, punter Andy Lee, to the Cleveland Browns. They saw enough from Pinion during OTAs to consider the much older and more expensive Lee expendable.

The learning curve for Pinion will be less than any of the other youngsters on this list because ... well ... he's a punter.

He had a net punting average of 39.2 yards during his career at Clemson. Add to that the 55 punts inside the 20 with only two touchbacks and there is no reason to believe that he will not perform well for the 49ers. He will hopefully only get better with time.

The added bonus for the team is that Pinion has experience kicking field goals, which could be an asset if kicker Phil Dawson hits a slump or the need arises for an emergency kicker. He has bragged about a 65-yard field goal that he made while training for the draft. Impressive, although it was unlikely to have had the same pressure as the same feat in an actual game. He also considers himself to be a good kickoff specialist. Maybe Dawson should watch his back too.

Of course, there are other young players competing for spots that could surprise in 2015. One of which may be wide receiver DeAndrew White, an undrafted free agent out of Alabama who, if he continues to impress as he has during the offseason, may give Jerome Simpson some competition for the slot receiver spot. Perhaps it is a long shot, but he has yet to show any signs of slowing down and has proven to be one of the favorite quarterback targets during OTAs and minicamp.

Dontae Johnson, the 49ers' 6-2 and 200 pound cornerback, looks to compete for the starting spot opposite Tramaine Brock. Having recorded a 4.45 40 and a 38.5 inch vertical jump at the 2014 NFL Combine, he certainly has the size and athleticism to excel. Like Hyde, the 2014 fourth-round pick has some good experience already, having played in all 16 games last season and even starting three. Although, he had an abysmal showing in the team's week 17 matchup against the Cardinals. Baalke seems to have confidence in his young cornerbacks because he passed on addressing the position in this year's draft.