ALLEN PARK -- When Jim Bob Cooter began installing his offense, he was a few thousand feet over the Atlantic. Literally.

It was the middle of the 2015 season. Joe Lombardi had just been fired, and the 31-year-old Cooter had been handed the keys to the Lions offense, making him the second-youngest playcaller in the game. And a couple hours later, he boarded a flight to London.

The game went about as you'd expect, a 45-10 blistering at the hands of Kansas City.

But he's continued to evolve, as has his offense. They finished seventh in the league last year in scoring. And that evolution will continue in 2018, with the hopes even loftier heights are ahead.

"You're always trying to look at the previous year and sort of improve and get better," Cooter said this week as Detroit geared up for the second round of OTAs. "I'm sure we'll change plenty, and I'm sure there will be a lot where you'll guys will look out and see some similarities. We're going to try and get better. Think we've identified a couple ways we think we can do that.

"Obviously," he added in characteristic dry-wit, "I'm not going to tell you anything about that."

While the changes to the offense remain a secret -- you didn't really think he was going to spill any beans, did you? -- the most notable differences when Detroit took the field last week were in the running game. Newcomers like LeGarrette Blount and rookie Kerryon Johnson had taken the place of Ameer Abdullah and Theo Riddick at the front of the running back rotation. Another rookie, Frank Ragnow, was repping as the starting guard. There was a new offensive line coach, Jeff Davidson, and it sure looks like an overhaul of the blocking concepts is under way.

Of course, there is a whole new position entirely as well. Fullback Nick Bawden was drafted in the seventh round, and he has competition too, with Nick Bellore -- listed as a linebacker -- wearing an offensive shirt and working full time at the position.

This comes about a year after Cooter had scrapped the position from his offense entirely. He declined to say whether that decision was his, or Jim Caldwell's, but he's clearly excited by the prospect of adding more two-back sets to his call sheet.

"I think that has an impact on the defense," Cooter said. "These days you're seeing a lot more one-back football out there and guys are having to defend both when you're playing a team that also plays some two-backs. So we're evaluating all that stuff. We're excited about the way our guys are coming along and sort of seeing where we end up as we're practicing all that."

If the changes really do resuscitate the Lions running game -- which has produced fewer yards than anybody in the league since 2015 -- perhaps this offense is indeed headed for better days. And remember, for all its ills, this is an offense that scored more points than all but six teams last year.

Get even average production on the ground, and this offense has the potential to be outright dangerous with Matthew Stafford back, and all four of his top receivers.

"We like our guys," Cooter said. "We like our guys. We've got a good group. We've got a smart group. They're working hard, trying to get better at this point in the year. We're expecting to have some fun this year. But I'm not in the prediction market. I'm not in the projection market. You know, we'll see what happens, we'll see what we can do."

Cooter's right to be cautious. After all, it was just last year that he was talking about spending his offseason studying running games, making that his priority, to acquaint himself with some of the finer nuances of some of the game's best ground games. And then Detroit finished last in the league in yards per game, yards per carry, conversion rate in short-yardage situations -- you get the picture.

This year, his personal evolution as a playcaller has continued to evolve. He's just playing his hand a little closer to the vest.

"I've learned at this point not to think that I have all the answers or even most of the answers," Cooter said. "I'm getting better every year. Every year I figure out something that I go, 'Man, a year ago I didn't see it that way and now I do.' I think I understand it better.

"This is a complex league. You got to stay fluid."

This year, Cooter didn't spin any tales of professional development. He doesn't pretend to have the secret sauce. But he is talking a little older, sounding a little wiser, and he believes his offense will reflect that. He cited one example of a route that he had been running 12 yards, which he's now lengthened to 14 after watching other teams' film.

Boring stuff, but the kind of stuff he believes will help Detroit's seventh-ranked offense continue to evolve for the better.

"I don't have some great story of going to some secret meeting somewhere and really hashing out the secret play that's going to break the NFL wide open. I don't think I pulled that off yet," Cooter deadpanned. "But we're always working to get better. I'm studying a million things. Trying for these little 1 percent improvements here, there, everywhere.

"It could be something that's obvious to you guys, to the fan at home. It could be something that's totally not obvious. But it may have a big impact at a certain moment."