The San Francisco 49ers used a sixth-round selection to acquire tight end Kaden Smith. With Garrett Celek sidelined — and that could last into the regular season — it seemed like an excellent opportunity for Smith to grab that top backup job behind Pro Bowl tight end George Kittle. But it might actually be a former undrafted rookie, not the sixth-round pick, in the lead for the job.

Matt Barrows of The Athletic, who has observed each practice of training camp, is impressed with the play of Ross Dwelley, and feels the San Diego product might be the frontrunner to back up Kittle.

That's not to say that Smith isn't faring well, just that Dwelley looks like the more polished tight end during practices.

The second-year player worked out in Nashville this offseason with Kittle and quarterback C.J. Beathard, worked with Nick Mullens a lot last year during preseason, and he's starting to get more reps with Jimmy Garoppolo this year.

"I'm kind of developing chemistry with all three of those guys," Dwelley told reporters on Sunday.

One thing Kittle excels in is blocking. For Dwelley, he acknowledges that's an aspect of his game that must improve.

"My biggest strength would just be how I catch the ball and how I run my routes," Dwelley said. "I've been working on my blocking a lot, so I'm trying to make that a strength in my game too […] The tight end is on the front side of a lot of blocks in this offense.

"[Tight ends coach Jon Embree] stresses if you can't block, you're not going to play because play-action is a big part of our game, so the tight end needs to be a big part of the blocking scheme. So I've definitely tried to improve that part of my game."

Dwelley was active for 11 games last year but had just two receptions for 14 yards. He could find his number being called on more often this season.

What does the second-year tight end think about his rookie competition?

"Kaden's a great dude," Dwelley said. "He works really hard. He comes from Stanford, which kind of runs the same pro-style offense as we've got here, obviously. So he's learning really quick, and he runs good routes, he blocks well, and he's a really good dude off the field, too."

Dwelley says San Diego also implemented a similar pro-style offense. The biggest difference for him is the speed of the game.

"Through OTAs last year, it was kind of a slap in the face," Dwelley said. "Like, wow, it's a lot faster, and guys are a lot stronger than at San Diego. But through training camp last year, I started getting the hang of it, and it's great having George and Celek as two solid veterans that are great dudes, and I can learn from them."

Dwelley is letting his play on the practice field speak for itself. He knows the 49ers coaches will have difficult decisions to make in a few weeks and will do whatever they feel improves the team.

"I'm just trying to stay humble and hungry, and keep grinding," Dwelley added.