The San Francisco 49ers kick off organized team activities (OTAs) on Monday, and it is the first time this offseason that coaches can pit the offense against the defense in non-contact drills.

There will be three practices a week over the next three weeks with one practice per week being open to the media. The first will be a scheduled noon session on Tuesday, May 21. OTAs will conclude on June 6 with a three-day mandatory minicamp the following week.

Here are five storylines to keep an eye on as OTAs begin.

Jimmy Garoppolo's knee … and arm


We are eight months removed from Jimmy Garoppolo's devastating knee injury. The quarterback has already gotten in some unofficial light throwing sessions with his teammates — like this one from San Jose State — but Tuesday will be the first time reporters get a glimpse.

Garoppolo says his rehab is coming along as planned and he still hopes to be the 49ers' starting quarterback when the regular season kicks off in September.

"The trainers, coaches, they're all putting together a pretty good plan of just how we're going to attack it," Garoppolo told ESPN earlier this month. "I'm excited to get back out there, finally."

Expect reports on Garoppolo to become routine until he gets up from that first big hit in an actual game. We still have a few months before that happens.

Backup quarterback battle


Head coach Kyle Shanahan isn't handing Nick Mullens anything. Despite an impressive eight-start performance in 2018, he will enter OTAs on equal footing with the 49ers' former third-round pick, C.J. Beathard. The two will receive the bulk of the practice snaps as the coaching staff determines who will be Garoppolo's backup.

Shanahan rarely carries two quarterbacks on the roster but briefly did so last season when the team signed Tom Savage.

Mullens, an undrafted free agent signed in 2017, clearly had better outings than Beathard. He finished the season completing 176-of-274 attempts (64.2 percent) for 2,277 yards with 13 touchdowns and 10 interceptions. Mullens' passing yard total through his first eight games ranks as the fourth-most in the NFL since 1970.

Beathard, through his past eight starts, completed 167-of-283 attempts (59.0 percent) for 2,035 yards with 10 touchdowns and 10 interceptions. He was 1-7 during that span while Mullens was 3-5.

Mullens is looking forward to the competition.

"I embrace it," he recently told the San Francisco Chronicle. "Competition brings out the best in people."

Improved pass rush


The 49ers invested heavily in pass rushers this offseason. While it will be tough to judge the impact during non-contact drills, it will be nice to see new bookends Dee Ford and Nick Bosa on the edges. San Francisco ranked No. 22 in sacks last year.

Who might benefit the most from an improved edge presence? DeForest Buckner.

The fourth-year defensive tackle racked up a career-high 12 sacks last season. Ford got to opposing quarterbacks a career-high 13 times in Kansas City last year. Most rated Bosa as the best overall player in last month's draft — not just the best defensive player.

"He's a great player," Buckner recently said on KNBR. "I see why they picked him at No. 2."

Having Ford and Bosa lining up on the edges should take some of the pressure off Buckner and allow him to see more one-on-one matchups.

"[Ford]'s been a really good addition for us, a really good guy around the (defensive line) room, and having in the room," Buckner said. "Just picking his brain on little things, and just bouncing ideas back and forth."

An abundance of wealth at running back


The 49ers added former Atlanta Falcons running back Tevin Coleman this offseason. He joins a room that already includes versatile players Jerick McKinnon and Matt Breida. Any one of those players being named the starter would not be that significant of a shock. It goes to show how much improving the running back depth meant to the 49ers as they prepare for the 2019 season.

Injuries devastated the position last year. McKinnon went down with an ACL injury before the start of the season. Breida's name consistently appeared on injury reports, but he still managed to play in 14 games with 13 starts.

Even special teams ace Raheem Mostert was lost to a forearm injury in November after being forced into action on offense.

Each of those players should be ready for the 2019 season, and if each remains healthy, the 49ers might boast one of the better running back groups in the league.

Identifying who will start opposite Richard Sherman


Veteran cornerback Richard Sherman's first year with the 49ers was injury-riddled. First, he was coming off of his rehab from an Achilles injury suffered the year before. Then he had to deal with a significant calf injury.

"I'm much healthier," Sherman recently told the Sacramento Bee. "I was kind of out there on one leg (last year)."

Even playing at about 80 percent by the end of last season, Sherman was clearly the team's best defensive back. He believes the pass defense will benefit significantly from the team's pass rush upgrades.

"We needed guys to hit (the quarterback) in the face," Sherman said. "You need a few of them. Now we have guys that can rotate in and rotate out and put pressure."

The real question is who will start opposite Sherman. Then-second-year cornerback Ahkello Witherspoon opened the year in that role. He struggled at times and, like other defensive backs, ended his season on injured reserve.

The 49ers brought in oft-injured free agent cornerback Jason Verrett. His last healthy season came in 2015 when he earned a trip to the Pro Bowl. That's the Verrett the 49ers hope they got.

Despite coming off of a torn Achilles tendon in 2018, the sixth-year cornerback believes he is progressing well and will be ready for the regular season.

"I'm just excited the 49ers gave me a chance," Verrett recently said on SiriusXM Radio.

Until Verrett has a chance to prove himself, Witherspoon will have to fend off other youngsters like Tarvarius Moore.

The 49ers defense had an NFL-record low two interceptions last season. Neither of them was by a cornerback.