At some point this season running back Christian McCaffrey is expected to get back on the field for the San Francisco 49ers.

McCaffrey is battling Achilles tendinitis that first cropped up in Week 17 last season. There was some hope he'd return for the season opener, but he missed that game before landing on the injured list where he's been since Week 2 with no firm timetable for his return.

His absence opened the door for third-year undrafted RB Jordan Mason to enter the fold, and Mason burst through it the same way he's burst through defenses for 609 rushing yards this season. That's the second-highest total in the league and a whopping 145 more yards than he had through his first two season combined.

There were some questions about whether he could contribute as an every-down player after his first two seasons. Mason has answered those questions authoritatively in the affirmative through six weeks this season.

While Mason's role will undoubtedly shrink once the reigning Offensive Player of the Year returns, it can't be diminished to what it was a season ago when Mason was largely an afterthought in any scenario that wasn't a blowout while McCaffrey was healthy.

To be clear, McCaffrey should still hold a substantial role in the offense. His presence will cure some of what ails them on that side of the ball with yards-after-catch and scoring touchdowns in the red zone.

However, Mason has proven valuable to the 49ers' offense with his ability to create yards after contact. That alone is worth having him on the field, but it becomes even more important considering what San Francisco is going to need to accomplish with managing McCaffrey's tendinitis.

They can't expect McCaffrey to step onto the field and average more than 21 touches per game. They also can't get away from their identity as a run-first offense. That means utilizing Mason more often early in games where he's taking some of the carries off McCaffrey's plate. It might even mean at some points using McCaffrey as a de facto third-down back to ensure he's fully healthy come playoff time. There are also some fun things they can do with McCaffrey and Mason on the field together where they're utilizing McCaffrey's skillset as a receiver to tie defenses into knots.

Ultimately the 49ers are in a good spot. They don't need to rush McCaffrey back thanks to Mason's success, and once he does return they don't need him to be the workhorse he was last season.

There's a sweet spot here for San Francisco where they maintain one of the NFL's best offenses without overdoing McCaffrey's workload and eliminating Mason from the picture during his breakout season.

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This article originally appeared on Niners Wire: Christian McCaffrey return shouldn't erase 49ers breakout star on offense