Marshawn Lynch is one of the hottest running backs in football, and he’s also on a touchdown tear.

Lynch has found paydirt at least once in each of his last 10 games and has five scores in the last three weeks. As a result, he’s now second in the league in rushing touchdowns among running backs (LeSean McCoy has 17, Lynch has 11).

But a streak will end Saturday at CenturyLink Field in Seattle, because the 49ers have, amazingly, not allowed a single rushing touchdown all season. For context, no other team in the league has given up fewer than six rushing scores.

Dating back to last season, they’ve now gone a total of 15 games without allowing a rushing TD — a streak matched only by the Bears in 1985 and 1986. But to set a new record in that category, they’ll have to stop Lynch. And there’s a chance they’ll again have to do so without the services of All-Pro middle linebacker Patrick Willis.

Lately, the Niners haven’t exactly drawn a scary group of opponents as far as the rushing touchdown threat goes. They’ve faced a limping Beanie Wells and the Cardinals twice in the last five weeks and went up against a struggling Rashard Mendenhall on Monday night. Their last five opponents have scored a grand total of 38 rushing touchdowns in 56 games this season.

While the average NFL team has scored a rushing touchdown in 78 percent of their games this season, San Francisco’s last 10 opponents have scored on the ground in just 64 percent of their contests.

As ESPN’s Mike Sando points out, Lynch has the highest touchdown percentage in the league when inside opponents’ three-yard lines. He’s a bruiser who has found his game since struggling early (including a poor performance against the Niners to open the season).

Two impressive streaks collide Saturday in Seattle. That’s just one intriguing storyline connected to one of the best games of Week 16.