The Dolphins began Sunday with three running backs. By halftime, they were down to two. By the fourth quarter, they were playing one.

That erosion parallels the erosion of good feeling for the Dolphins as they went from a 10-0 lead on the Jets to a 23-20 overtime loss. Sunday with the running backs also begs questions of personnel deployment as well as end-of-the-half strategy.

First, Reggie Bush became the second Dolphins running back in three games to suffer an injury as the Dolphins ran the ball at the end of the first half instead of just kneeling down. The Dolphins sat on their own 20-yard line, first and 10 with 36 seconds left in the half. The Jets had two timeouts left. Bush came off the field favoring his left knee. During the third quarter, he rode the exercise bike and jogged behind the Dolphins bench, but eventually returned to the locker room.

In his postgame media session, Dolphins coach Joe Philbin claimed ignorance at how badly Bush’s left knee was damaged. A source told The Herald the knee stiffened on Bush, who wanted to continue. It should be checked further Monday but shouldn’t be a season-threatening problem.

That took some pop out of an offense with precious little. Last year, the seven longest Dolphins runs all belonged to Bush. Only 11 Dolphins running plays all season exceeded 20 yards.

Two weeks ago, down 17-3 with 35 seconds left in the first half at Houston with the ball on their own 30, the Dolphins chose to run the ball instead of doing two kneel downs. Only one Houston timeout remained. Thomas carried, got cracked into a fumble and concussion, Houston scored another touchdown and Thomas missed last week’s game against Oakland.

“Reggie bush is Reggie Bush,” Dolphins fullback Jorvorskie Lane said. “The [Jets] defense might look at [rookie Lamar Miller] and let up a little bit because…it’s Reggie Bush. But I think Lamar did a hell of a job and picking up the slack.”

Sunday, Bush’s injury left Thomas and rookie Lamar Miller. Thomas ran for 31 yards on 11 carries in the second half while Miller got all of his 48 yards on nine third quarter carries. But Thomas also fumbled on his second carry of the quarter, giving the Jets the ball at the Dolphins’ 26.

(Chris Clemons’ end zone interception took that Jets’ possession off Thomas’ account)

“Just trying to get extra yardage,” Thomas said. “I had it high and tight, but it was just a good play defensively.”

The Dolphins got 38 rushes for 178 yards and a touchdown from Bush, Thomas and Miller for the game. But Bush and Miller ran 19 times for 109 yards, 5.7 yards per carry, while Thomas ran 19 times for 69 yards, 3.6 per carry. Perhaps Thomas’ more physical style plays to the Jets’ strength while Bush and Miller bring more boogie to counter the Jets’ brutishness.

Whatever the reason, it begs the question why the Dolphins didn’t use Miller in the fourth quarter. Most rookie running backs take time to figure out their proper role in pass protection. Coaches don’t like their quarterbacks blasted. They also don’t like fumbles and Thomas has two fumbles in two games.

“We wanted to give Lamar an opportunity once we thought Reggie couldn’t play effectively,” Philbin said. “We have two guys, we think a lot of both and we think they’re both capable of playing. Some of it was dictated by situation, but some of it was spreading the carries around.”

Herald sports writer Armando Salguero contributed to this report.