Bruce Miller 49ersSince making the transition from defensive end to fullback as an NFL rookie, Bruce Miller has been an integral part of the San Francisco 49ers’ offense. Frank Gore hailed Miller’s football intelligence on Friday, complimenting him in the way only Gore can.

“He’s really not a practice player,” Gore said. “He’s so smart. I know that if in practice he doesn’t get a block, I know in the game he’ll make that block. He’s a very smart football player.”

Miller’s blocking has been strong throughout his career, and he’s also a valued special teams contributor. What he hasn’t been asked to do all that often is carry the ball, either as a rusher or as a receiver out of the backfield. Fullbacks don’t often carry the ball in today’s NFL, and the 49ers have a pretty deep stable of rushers headed into this season led by Gore. But with Michael Crabtree and so many other 49ers receivers dealing with various injuries, it seems like the only guy who hasn’t been mentioned much as someone who could pick up some of the slack is Miller.

Since Jim Harbaugh took over, the running backs haven’t been all that involved in the passing game as receivers. Gore is a tremendous pass blocker, but his receptions per season have dropped from an average of 51 per season in the five years before Harbaugh took over to 22.5 per season over the last two years.

Miller caught 11 balls for 83 yards in his rookie season, and last year his numbers was almost identical: 12 receptions for 84 yards.

Running backs coach Tom Rathman, undoubtedly the best pass-catching fullback in franchise history, caught 13 passes for 121 yards in his first season. From there his role in the passing game grew dramatically, as his receptions jumped from 30 to 42 to a career-high 73 catches for 616 yards in 1989 (back in the era when announcers were contractually obligated to use the phrase “so many weapons” any time they referred to the 49ers).

I asked Miller about Rathman’s evolution as a receiver, and whether Miller could see himself following in his position coach’s footsteps in ways other than blocking. Miller laughed.

“I hope so. I’d like to see 70 balls a year. Right now, just working to fit into the system. Whatever they want me to do, block, catch balls, doesn’t matter,” said Miller, who let on that things might change in 2013.

“It’s going to be exciting this year. I think my role is going to expand a little bit.”

That last part makes sense, and not just because he’s a third-year player and the 49ers will be without Crabtree and Delanie Walker next year, two guys who saw a lot of passes in 2012. Colin Kaepernick targeted the 49ers fullback nine times, leading to nine catches for 54 yards. Alex Smith targeted him only four times, resulting in just three catches for 30 yards. And based on what I’ve seen during OTAs and just one training camp practice, Kaepernick definitely values Miller as an option in the flat.

What remains to be seen is whether that’ll lead to Miller getting more chances to do his best Rathman impression. There’s one minor problem with that idea: Rathman doesn’t want his players spending all their time in the film room watching old No. 44 tapes.

“(Rathman) hides it from us. He won’t let us dig into those films because he knows we’ll give him a hard time. I’ve seen him and he’s talented, he played it the best it’s been played. I do like to dig and find some film of him … I think he hides them from us because they were so good. He doesn’t want to be boastful,” said Miller, who after mining for Rathman footage was impressed by several things.

“The way he catches. Everyone knows what a hard-nosed blocker he was, I knew I was going to find that. But the way that he carried the football and caught the football out of the backfield, he was scoring touchdowns all over the place. It’s fun to see.”

The NFL is different now than it was during Rathman’s (and the 49ers’) glory days of the late-1980s, and Harbaugh isn’t a carbon copy of Bill Walsh. But I’d be surprised if Miller’s role in the passing game didn’t evolve in 2013. Maybe not to the extent we saw from Rathman (who caught 320 passes in his nine-year career), but Miller should get at least two or three targets per game on average.

If that doesn’t happen for whatever reason, Miller — often finds himself in front of the 49ers’ all-time leading rusher — will almost certainly follow Gore’s lead, at least from an attitude standpoint. When asked about catching fewer balls in the two seasons since Harbaugh arrived than under previous regimes, Gore had this response:

“The last two years, right? We’ve been winning, so that doesn’t matter. The years I had a lot of catches, we weren’t doing so well.”