HOUSTON – The beginning of the NFL season is finally here as Houston Texans fans flocked to NRG Park for the first day of training camp on Sunday.

Unfortunately for the team and its fans, two star players were not on the field.

Wide receiver DeAndre Hopkins was holding out while seeking a new contract. Hopkins has been playing under his rookie contract signed in 2013 as the team's first-round selection.

Hopkins released a statement to ESPN Sunday afternoon saying that he is disappointed the Texans won't negotiate a new deal, but he will practice.

#Texans have officially moved DeAndre Hopkins from Reserve/Did Not Report List to Active roster. T Jeff Adams also now active, off PUP list — Adam Wexler (@KPRC2AdamW) July 31, 2016

The team exercised the fifth-year option on his contract in April, meaning he has two years remaining on his contract.

"That's between my agents and the Texans," Hopkins said last week. "I love this city, I don't want to play anywhere else but here. The rest will work itself out, hopefully."

On the other side of the ball, star defensive end JJ Watt is recovering from back surgery and is expected to miss training camp and the preseason.

"I'm glad we found it and took care if it. Will get me healthy for the season," Watt said. "I feel good and my body feels good. I am just listening to my doctors."

Osweiler " training camp is a grind and it is all about embracing that grind" #Texans #TexansCamp pic.twitter.com/jdNhITmY7h — Randy McIlvoy (@KPRC2RandyMc) July 31, 2016

One player fans did get a look at was new starting quarterback Brock Osweiler.

"Training camp is a grind and it is all about embracing that grind," Osweiler said. "With DeAndre being one of your go-to guys and not being here, it's difficult, but I totally understand what he's doing."

Head coach Bill O'Brien said the players worked hard and came to camp in good shape.

"Operationally it was a good day, especially for first unit," O'Brien said. "You just have to coach the guys that are here."

Several players signed autographs for fans.

More than 4,600 fans were in attendance Sunday.

Here's the schedule for the remaining camp practices that are open to the public. Make sure to check HoustonTexans.com to see if any free tickets are left.

Tuesday, Aug. 2 8:30-11 a.m.

Wednesday, Aug. 3 8:30-11 a.m.

Saturday, Aug. 6 8:30-11 a.m.

Sunday, Aug. 7 8:55-11 a.m.

Thursday, Aug. 18 TBA

J.J. Watt Overview | PointAfter

DeAndre Hopkins Overview | PointAfter