Yes, I believe it was an illegal bat. The penalty would have been 10 yard assessed from the previous spot and an automatic first down.
Rule 12, Section 1
Illegal Bat
Article 8 A player may not bat or punch:
(a) a loose ball (in field of play) toward opponent’s goal line;
(b) a loose ball (that has touched the ground) in any direction, if it is in either end zone;
(c) a backward pass in flight may not be batted forward by an offensive player.
Exception: A forward pass in flight may be tipped, batted, or deflected in any direction by any eligible player at any time.
Note: If a forward pass that is controlled by an airborne player prior to completing the catch is thrown forward, it is an illegal bat. If it is caught by a teammate or intercepted by an opponent, the ball remains alive. If it is not caught, the ball is dead when it hits the ground.
Penalty: For illegal batting or punching the ball: Loss of 10 yards. For enforcement, treat as a foul during a backward pass or fumble (see 8-7-7).
