President Trump took a subtle jab at the NFL during his first official State of the Union speech on Tuesday night, praising the respect Americans show for veterans when they stand for the national anthem.

Trump was praising Preston Sharp, a 12-year-old who was a guest of first lady Melania Trump after he helped ensure American flags were placed on veterans' grave sites. He never mentioned the NFL directly, but said Preston reminded the nation about the importance of standing for the national anthem.

“Preston's reverence for those who have served our nation reminds us why we salute our flag, why we put our hands on our hearts for the pledge of allegiance, and why we proudly stand for the national anthem,” the president said.

Sharp, of Redding, Calif., placed 40,000 American flags on veterans graves after noticing many were not adorned by flags on Veterans Day.

“Preston, a job well done,” Trump said.

The president has sparred frequently with the NFL and players who kneel during the national anthem. In a speech last year, he called for NFL owners to fire players who take a knee while the Star Spangled Banner plays.