Mac Jones appeared to show his age Sunday at Gillette Stadium.
Early in the third quarter of the New England Patriots' matchup with the Tennessee Titans, the rookie quarterback scrambled for about eight yards on a third-and-10.
Jones was a good two yards short of the first down but signaled like he reached the marker, and social media called out the 23-year-old for his apparent brain fart.
So, why the first-down celebration when Jones clearly came up short? The rookie explained that he thought Titans cornerback Buster Skrine would be flagged for a late hit after Jones tried to give himself up on the slide.
"You talking about the one I ran on and thought I got the first down?" Jones said with a laugh in his postgame press conference, as seen in the video above. "I didn't think I got the first down. I thought they were going to call (a penalty). I slid head-first or whatever but it didn't count.
"It is what it is. I didn't know there wasn't a flag thrown. That was just a rookie error there."
Jones' explanation makes sense; Skrine's hit would have been a penalty had Jones slid fully feet-first. But because Jones turned at the last second and slid on his side, Skrine's hit was legal.
Patriots wide receiver Kendrick Bourne -- who caught two touchdown passes from Jones on Sunday -- came to the defense of his quarterback after the game.
"We should have got a penalty on that," Bourne said. "Looked like targeting to me."
Jones had an otherwise strong day, completing 23 of 32 passes for a career-high 310 yards and two touchdowns in the Patriots' 36-13 rout of Tennessee. So, he earned the right to laugh off his "rookie error."