EAST RUTHERFORD, N.J. — Mark Sanchez heard someone chuckle as his mouthpiece fell to the turf before his first snap for the New York Jets.

“I said, ’Green-30,’ and boom, my mouthpiece came out and the defense was laughing,” Sanchez said. “I thought, ’What an idiot.”’
The rookie quarterback was feeling a lot better about himself a few seconds later, completing a 48-yard pass to David Clowney on his first NFL play Friday night. It was the start of an early scoring drive in New York’s 23-20 preseason loss to the St. Louis Rams.
“When Mark came in, he looked like he’s been looking in practice,” said Rex Ryan, who had his head coaching debut spoiled by the loss. “He stepped in and it wasn’t too big for him.”
Sanchez, who came in with 28 seconds left in the first quarter, was surprised when he got the play call from offensive coordinator Brian Schottenheimer.
“I said, ’Man, he’s going long our first play,”’ Sanchez said. “I said, ’Here we go, man! Let’s go! Let’s do it! Dial it up!”’
Seven plays after the pass to Clowney, Thomas Jones took a handoff and leaped over the pile from a yard out, the ball crossing the goal line before it was knocked out of the running back’s hands. St. Louis’ Steve Spagnuolo, a winner in his head coaching debut, challenged the call, but it was upheld by video review.
Sanchez, with several family members in attendance, completed three of four passes for 88 yards.
“I think he showed us everything we needed to see,” Ryan said.
Kellen Clemens, competing with Sanchez for the starting job, completed all four of his passes for 24 yards and was sacked once in two series.
Ryan, disappointed with the loss, saying “it stinks,” wasn’t ready to name a starter for the next game at Baltimore on Aug. 24.
“We’ll just continue to compete and improve until (Ryan) is ready,” Clemens said. “And, hopefully after that, we’ll have a clear No. 1 and 2.”
Trailing 20-16, St. Louis took advantage of a muffed punt return by the Jets’ Paul Raymond to get the ball deep in New York territory. Rookie Keith Null, who came on in place of the injured Brock Berlin, put the Rams back ahead three plays later on a 13-yard touchdown pass to Sean Walker with 7:32 remaining.
“I went and got the ball for (Null),” said Rams starting quarterback Marc Bulger, who was 4 of 4 for 77 yards in three series. “I told him, ’Who cares if it’s preseason? It’s still your first touchdown pass in the NFL.’ That pass looked like a 10-year veteran.”
Spagnuolo, who interviewed for the Jets job, won in his return to the Meadowlands after being the defensive coordinator for the Giants the last two seasons.
“I have great memories here,” Spagnuolo said. “I was not wrapped up in that. I just kind of get into a little bit of zone.”
Erik Ainge, 10 of 17 for 148 yards, put the Jets ahead 20-16 with 10:27 left when he playfaked and found Clowney wide open down the middle of the field for a 50-yard touchdown. Clowney had three catches for 102 yards.
Samkon Gado, trying to make St. Louis’ roster as Steven Jackson’s backup, had a 77-yard touchdown run 25 seconds into the third quarter that gave the Rams a 16-10 lead.