When it comes to certain offensive records, you can never say never.
Dan Marino shocked the world when he threw 48 touchdown passes in 1984. Fans marveled at 30-touchdown seasons by quarterbacks and the concept of three touchdowns a game didn't seem possible. But Marino did exactly that.
The record for touchdowns scored in a season is the latest record under attack. LaDainian Tomlinson scored his 29th touchdown last Sunday to break Shaun Alexander's record of 28 set just a year ago. In 1995, Emmitt Smith scored 25 touchdowns. In a passing league, that was an amazing accomplishment.
But Smith's NFL touchdown record has been broken four times this decade. Marshall Faulk had 26 in 2000. Priest Holmes had 27 in 2003. Alexander scored 28 last season. Tomlinson has three games to tack on to his record of 29.
"I never really thought about it," Alexander said of where the touchdown record could go. "I think people set goals. Once you realize something you never thought, then people start going after it. I never thought about the record until Priest Holmes scored a bunch of touchdowns. Then you start thinking, `Maybe I can do it."'
Even if Tomlinson tops out the record with two touchdowns a game over his last three games and finishes with 35, it's not out of the question for others to challenge it in the future. Look at the Marino's then-record; most people probably thought it wouldn't be broken.
Then along came Peyton Manning. He revolutionized the position by getting back to adjusting the plays at the line of scrimmage. Quarterbacks called plays in the 1970s, but it was a running league then and there weren't many multiple formation sets. Manning threw 49 touchdown passes in 2004 and could have easily taken the record into the 50s if he and the Colts were greedy. They weren't.
Like Manning, Tomlinson isn't about setting records. He's about winning. Tomlinson has it all. He has a jump cut that is impossible to stop. He'll step one way to draw defenders and then cut to the other way, leaving those defenders reaching for air.
Near the goal line, he's particularly amazing. He is fast to the hole, which makes him exceptional at scoring on quick inside running plays. If he takes the run to the outside, he's fast enough to beat containment. His leaping ability is exceptional, and he has a knack for timing his jump correctly.
Then you add in the nasty aspect of a halfback option pass and he's even harder to defend. At any given moment, Tomlinson could stop with all the defenders pursuing him and toss a touchdown pass to Antonio Gates. It's a play that works almost every time the Chargers call it.
Football goes in cycles and Tomlinson, Alexander, Holmes, Faulk and others are playing at the right time to take this touchdown record to new levels. One thing that is aiding this touchdown binge is a subtle choice by offensive coordinators to spread the field as they approach the goal line.
Back in the Warren Moon days when a couple of teams experimented with the Run-and-Shoot offense -- a wild passing set in which teams operated with four receivers and one back -- old-timers grumbled that it was a foolhardy concept. Not tough enough, they said. Too much finesse, they grumbled. Moon would drive the ball from 20-yard line to 20-yard line with ease, but the red zone became a problem.
There wasn't enough of a plan to power the ball when they got closer to the goal line. For one thing, tight ends weren't part of the nix. The old Houston Oilers teams replaced the tight end with a possession receiver, and they struggled for touchdowns inside the red zone.
Now, offenses will spread the field with three receivers and keep a tight end on the field when they get inside the 10 and it's creating great opportunities for the running backs. As Tomlinson nears the goal line, opponents face tough decisions. Do you stay in your base defense to provide more tacklers for Tomlinson or do you put in extra defensive backs to guard against the pass?
The Chargers and coach Marty Schottenheimer can take scoring to even higher levels in the next year or two. The current team has the perfect storm of talent and creativity.
First, the Chargers have Tomlinson. "He's like Marcus Allen when I had him in Kansas City when he's near the goal line," Schottenheimer said. "With Marcus, you know he was coming near the end zone, but they still couldn't stop it. Like Marcus, LaDainian has an understanding of what to do."
Second, they have a great play-caller in offensive coordinator Cam Cameron. Cameron comes from Don Coryell's "Air Coryell" school of offense. He worked with Norv Turner when they were with the Washington Redskins. Turner brought the "Air Coryell" offense to Troy Aikman and the Dallas Cowboys.
Third, they have tight end Gates, one of the top red zone tight ends of this era. Gates is a former basketball player who can outjump defenders on fade passes and is strong enough to bang a linebacker and box him out to be in position for a touchdown catch.
"Defenses have to decide what to do with Gates," Schottenheimer said. "Because of him, you don't get a lot of goal-line defenses. You can put him on the outside like a receiver and you force teams to make decisions. Some teams will just stay in base defenses and that creates an opportunity to run it in from two or three yards."
Along with his blockers, a running back's best friend in the red zone is the tight end. A tight end like Gates can remove the clutter of goal-line defenses to make it easier for Tomlinson to score touchdowns. The Gates-Tomlinson combo is one of the most talented red zone combos in NFL history.
"A tight end is so important in the red zone," Alexander said. "Anytime you have a big body tight end, you can do so many things."
But let's tip the cap to Tomlinson. He's been the game's best running back for years. In his sixth year, his talents seem to be peaking.
"He's the best running back I've ever seen," Schottenheimer said. "LaDainian can do everything a running back needs to do to be successful. I know Jim Brown is the gold standard of running backs. He was as big as some of the defensive linemen trying to tackle him. I think LaDainian is the best I've seen."
Where this touchdown record is going is anyone's guess. The next back who could make a run at Tomlinson's record other than Tomlison himself is Larry Johnson of the Chiefs. He's a back with 2,000-yard ability and he's amazingly durable. As long as Tony Gonzalez re-signs after the season, Johnson will have a great red zone threat at tight end.
So whatever number Tomlinson's number ends up at, don't fall into the trap of saying that it's never going to be topped. Until defenses find the right schemes for the spread sets and big pass-catching tight ends, the red zone will the be green light territory for some of the NFL's best running backs.
John Clayton is a senior writer for ESPN.com.