It’s tough to say with certainty who’s been the best player on the 49ers defense this season. Has it been Patrick Willis? Or NaVorro Bowman? Or maybe Aldon Smith?

Profootballfocus.com says it’s been Justin Smith, but they don’t stop there. They describe Smith as the “highest graded defensive player” in the league so far in 2011, and they rank him eighth in the running for the league’s MVP award.

They credit Smith with a league-leading 36 combined quarterback sacks, hits, and pressures. They also point out that Smith is “dominant in run defense, too.”

At the beginning of the season, few people considered Justin Smith the best defensive lineman in the Bay Area – Richard Seymour got that honor. Now, Smith is playing like the best defensive lineman in the NFL, and perhaps the best defender, period.