PHOENIX -- In a Week 2 victory over the Oakland Raiders last season, then-Miami Dolphins running back
Raiders head coach Dennis Allen had a front-row seat.
"I think he's extremely versatile," Allen said of Bush. "He can do a lot of different things. His ability to get out the backfield, whether it be by alignment or motion or after the snap.
"His ability to get into open space and do things out of the backfield in the passing game really makes him a weapon."
As a team, the Lions had four such runs in 2012.
"I thought Reggie had probably his most productive year as a running back last season," said Cincinnati head coach Marvin Lewis, who lost a 17-13 contest to Bush and the Dolphins in Week 5 last year.
"I thought he was better as a protector. I thought he was better as a runner. I thought he did a great job."
Bush proved the last two seasons in Miami that he's a complete running back. He amassed more than 2,000 rushing yards in 312 carries being asked to carry the load for the Dolphins' run game. He averaged 5.1 yards per touch.
"One of the impressive things about Reggie, he was all football," Detroit Lions general manager Martin Mayhew said of Bush's free agent visit to Detroit last week.
"He was all football and that's what we talked about. Even after he signed his contract, one of the first things he said is, 'where can I get a playbook?' That was his thing. Immediately. I mean, the ink wasn't even dry on it and he wanted to find out where he could get a playbook because he was ready to get going."
When asked how Bush might fit in with the Lions, Allen said defenses will have fits trying to come up with an effective plan to stop both him and All-Pro receiver
"I think they'll feed off each other," said Allen, who was the Denver Broncos' defensive coordinator before becoming the Raiders' head coach last season. "There's not going to be a philosophical change, I wouldn't suspect, with what (Detroit) is going to do offensively.
"I would think defensively, you still have to make sure you have coverage on Calvin. I think that's the most important thing you have to do. The ball travels farther and faster through the air than it does on the ground."
The Lions' offense led the league last year with 67 passing plays of 20-plus yards and ranked in the top 10 with eight of 40-plus yards. It should be noted they also led the league is pass attempts with 740.
"Everybody gets impatient, so if the running game is hurting you, eventually, as a defensive guy, you have to put another guy in the box and now all of the sudden Calvin is getting one-on-one coverage," Allen said. "I think those things will play off each other."
Johnson himself is also looking forward to that predicament opponent defenses should find themselves in.
"You have to be honest if you're the defensive coordinator when we get to the red zone," said Johnson. "Teams were able to take me away with two people last year.
"They won't be able to do that anymore because we have such dynamic players (such as) Reggie."
Teams will have to keep the Lions honest with Johnson, said Allen, but it won't be as easy to contain the offense using that strategy now that Bush will be in the backfield.
"There are a lot more explosive passing plays," said Allen, "so you have to make sure you handle Calvin, which is going to open up a lot of things for the running game, especially with a guy like Reggie, who is so great in the open space.
"I think Reggie will feed off that."