Rookie Dak Prescott looks like the Cowboys' answer at backup QB

There's been a ton of talk and numerous names thrown around since the Dallas Cowboys lost backup QB Kellen Moore to a broken ankle.

Nick Foles. Michael Vick. Johnny Manziel!

The speculation on who'd back up Tony Romo ranged from the sublime to the absurd. On Saturday night, Dak Prescott seemingly put an end to all of that.

The rookie from Mississippi State shone for the first half of Dallas' preseason opener at L.A., completing 10 of 12 passes for 139 yards and two TDs, with both incompletions coming on drops by Geoff Swain.

Prescott hooked up with Dez Bryant on a 10-yard score against cornerback Coty Sensabaugh in the first quarter ...

... then lofted a perfectly placed 32-yard throw over Lamarcus Joyner to Terrance Williams en route to a 21-7 lead.

Prescott sat out the second half as the Cowboys' other backup, Jameill Showers, led the offense. And Showers was capable, finishing 8 of 16 for 99 yards and showing good mobility. And turning in the most exciting play of the night:

But the offense stalled and the Rams rallied for a 28-24 win behind Sean Mannion -- the seemingly forgotten man in the Rams' QB competition.

However, Prescott's performance had to give the Cowboys confidence that they had found their backup QB.

"The best thing about Dak is that he is extremely calm," Bryant said. "It's like he's been here before. He's not playing like a rookie. He is going to be very good. He's special."

The Associated Press contributed to this report.