DETROIT – When Damon Harrison faced one blocker on Sunday afternoon, usually it meant rough things for the Seattle offense. On this particular play, the newly acquired Detroit Lions defensive tackle pushed D.J. Fluker – a teammate of his last year with the Giants – into the backfield and then moved away quickly enough to get his hands on Russell Wilson.

It went for a 10-yard sack and was the epitome of what the Lions were hoping for when they traded for Harrison less than a week ago. Sunday's game was always going to be a learning point for Harrison, who had practiced with Detroit for two days before stepping onto the field and playing about half of the snaps in a 28-14 loss to the Seahawks.

“I didn’t play well enough for us to win,” Harrison said.

What he did do, though, was offer a glimpse of what the Lions could be in the future as he becomes more comfortable. Harrison said after Sunday’s loss that he’s still picking up the playbook – one that was described by Lions defenders in the offseason as one that takes time to learn – and declined to give a percentage of how much of it he knows.

And as he learns more, it can only be a benefit for Detroit, whose next five opponents all have good run games: Minnesota, Chicago twice, Carolina and the Los Angeles Rams.

“He had a good impact because people now are going to focus on him,” said defensive tackle Ricky Jean Francois, who often rotated with Harrison on Sunday. “You can’t not focus on ‘Snacks.’ If you do that and leave him one-on-one, he’s going to make every play. Every time.

“We’ve got to learn how to play off of him. A guy like that, with All-Pro, top three, maybe No. 1 in run stopping, we got to learn how to play off that dude. We have to. That’s the only way we’re going to be able to stop the run. That dude right there, we got to learn how to play off him.”

That will come with increased knowledge of the playbook. And while the overall rushing numbers looked bad for Detroit’s defense – 4.2 yards per rush allowed and 176 yards – not a lot of the bigger plays were Harrison’s fault.

In my own rewatch of the game, Harrison was accounted for on the field on 38 snaps (the official book had him at 39) and that led to a productive day. He had seven tackles – all combined – along with a sack, two tackles for loss and a quarterback hit.

On those snaps, two were wiped out by penalty, 26 were runs and 10 were passes. Harrison was on the field for all four Seahawks touchdowns, although none was close to his fault. On Chris Carson’s touchdown run in the fourth quarter, Harrison actually ate up the space in the middle, which appeared to force Carson to cut back outside, where he found room and an eventual score.

Of the 26 runs, 11 ended up going for 4 yards or more when Harrison was in, but some of those went to the outside, where Harrison would have little impact. That includes a jet sweep by Tyler Lockett that went for 16 yards.

Harrison appeared to command double-teams on about half of the runs Seattle had while he was in the game. When he was single-covered in the run game, opponents either ran away from him or he did enough to influence the play. Linebacker Jarrad Davis seemed to be a beneficiary, as the holes Harrison’s space-eating created gave Davis gaps to run through to try to make tackles up the middle.

Harrison didn’t get as much push when Seattle passed the ball – not a surprise because that isn’t his forte – and was stood up on at least two plays by Seahawks linemen in passing situations. He was also on the field for all four Seattle touchdowns, although three were passes.

Overall, the way Harrison played gave the Lions belief their defense can get better over the second half.

“He just commands double-teams,” linebacker Eli Harold said. “You can’t single a guy like that. You can sense it. When he was on the field, I felt they were blocking him a different way than the other guys. I mean, he’s the best run-stopper in the league, by far, the past two, past three years.

“Having a guy like that, it really helps you out and helps open something else for another guy. But ultimately, man, we just got to get better as a run defense.”

And that’s why the Lions traded for Harrison in the first place.