Big changes are coming.

The fireworks we saw from the Texans offense in a five-game stretch from Week 3 through Week 8 last season, will look different in 2018.

Deshaun Watson is expected back under center after a tantalizing start to his career, but his head coach said the offense is undergoing an overhaul of sorts.

"We have to build it up again," Bill O'Brien said on Tuesday morning. "Start building a new offense. Our offense is totally different now from what it was."

O'Brien, who is in Orlando for the NFL Annual League Meetings, met with the media for an hour. He explained why the Texans will jiggle things up on offense in 2018.

"All these teams, especially in our division, have watched all those plays," O'Brien said. "They're studying those things, and we have to start from scratch."

Watson played in eight games last season, and started seven. He completed 61.8 percent of his passes for 1,699 yards, with 19 touchdowns and eight interceptions. The Texans averaged 26.9 points per game in those first eight. In his seven starts, that average rose to 29.7. But in the month of October, when receiver Will Fuller returned from injury, Watson and the Texans put up 40.5 points per contest.

Still, O'Brien said Watson and the Texans have to forget 2017 and move forward.

"We all have to get beyond last year," O'Brien said. "Last year's over, for all of us. 2017 is over. When we start again on April 16th, he has to start from scratch. He's gotta go right back to the basics of the offense. His own fundamentals, as much as he can work on that."

Watson went on injured reserve with a knee injury in early November, and O'Brien said the quarterback is progressing nicely in his rehab process. The Texans will start the offseason conditioning program a week from Monday.