ST. LOUIS (AP) Rob Boras will be calling plays for the first time in a dozen years on Sunday. Only two days into the new job, the new offensive coordinator for the St. Louis Rams knows game day will be an eye-opener.

''I'd be lying if I said no,'' Boras said after directing his first practice on Wednesday. ''It's not going to be perfect. Football isn't perfect.''

Coach Jeff Fisher said Boras was ''sleep deprived, as you would expect.''

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''He did a nice job today,'' Fisher said. ''Players are excited. We're moving forward.''

The 50-year-old Boras replaces Frank Cignetti, who was fired a day after the Rams (4-8) had a season low for scoring in a 27-3 loss to Arizona on Sunday. St. Louis has lost five in a row and is 31st in total offense, last in passing.

The offense will look the same this week against Detroit, but Fisher is hopeful it'll be a lot more efficient. When making the move, Fisher also said he hoped it would ''stimulate the staff.''

''I don't know how much can change,'' Boras said. ''We have different thoughts but we're pretty far down the road right now.''

Boras said it came as a total surprise when Fisher made the change, and he has been cramming ever since, saying he's communicating with his wife via emoji instead of texts to save time.

''This week seems about a month,'' said Boras, who was an assistant head coach/offense and tight ends coach with the Rams before the change. ''You don't have to type a whole word, I can just type a heart.''

Players were surprised by the move, too.

''I think everybody was a little bit,'' tight end Jared Cook said. ''You just roll with the punches, that's all you can do.''

Wide receiver Tavon Austin said he texted condolences to Cignetti.

''Things don't always go the way they're supposed to happen,'' Austin said. ''We've got to keep pushing.''

Boras will be calling plays for the first time since 2003 when he was offensive coordinator for UNLV. Among the goals are getting more touches for rookie running back Todd Gurley, who has been stifled in recent weeks.

Gurley has just nine carries each of the last two games.

Boras will be working with quarterback Case Keenum, who missed the last two games with a concussion but reclaimed the job over slumping Nick Foles. Keenum was a full participant for the first time since the injury.

''Cig was my guy,'' Keenum said. ''It's a production business and I've been fired three times, and it won't be the last time that I'm fired, either.''

Keenum said he remembers everything from the play he was injured, from the back of his helmet slamming the turf to a conversation with trainer Reggie Scott to the last two plays. He said he was a ''little shaken up,'' but didn't have symptoms until after the game.

''It's hard to say in the heat of the moment what you're feeling during a game,'' Keenum said. ''You don't really have time to think about how you're feeling when you're trying to make a play.''

Keenum was surprised to be at the center of a controversy about handling concussions.

''Obviously, it got blown up pretty big,'' he said. ''I have 100 percent trust in my training staff and my coaches that they wouldn't put me out there if they didn't feel I was 100 percent ready.''

Keenum said he has been ''completely honest'' with staff about how he is feeling, and that's why he hasn't played the last two weeks.

''Reggie and I are like an old married couple like, `What are you thinking about buddy? What are you feeling?''' Keenum said. ''He was always asking and he was always there.''

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