Texans defensive end J.J. Watt has never missed a regular season game, but there's a chance that could change in 2016.

According to the Houston Chronicle's John McClain, Watt underwent back surgery this week and is expected to be on the physically unable to perform (PUP) list when the Texans take the field for their first practice of training camp on July 31.

Watt's back was one of almost a dozen parts of his body that were bothering him when the 2015 season ended.

"Last year (2015), was definitely by far the most strenuous on my body that I've ever had, fighting through a bunch of things that I've never dealt with before," Watt told SportsRadio 610 in March. "We had the broken hand. I had a herniated disk in my back halfway through the year. I had, obviously, everything that went on with my groins and I don't think everyone fully understand what that process was like."

The Texans need J.J. Watt to heal fast. USATSI

Not only did Watt have to deal with a herniated disk and broken hand in 2015, but he also had to deal with five fully or partially torn core muscles, including a tear in his groin.

Ouch.

It's not yet known if Watt will miss any games in 2016, but it could happen. According to NFL.com, it could take up to 10 weeks before Watt's healthy enough to play, which means he would be out for the Texans' first two games of the regular season (Bears, Chiefs).

On the other hand, there's a chance that Watt won't miss any games. McClain has reported that the three-time Defensive Player of the Year "should" be ready for Houston's regular season opener against the Bears.

For the Texans, the downside of Watt trying to fit his recovery into such a tight time-frame is that if the defensive end suffers any kind of setback during rehab, that could potentially lead to Watt missing several games.

Watt went through a similar situation in 2012 when he missed the entire preseason with an elbow injury. However, not only did he return, but he ended up playing in all 16 games and winning his first Defensive Player of the Year award.

As things stand, Watt will start camp on the preseason PUP list. A player who is placed on the PUP list before training camp starts can be taken off at any time.