JTO's dilemma: Fourth quarter and third downs

While quarterback J.T. O'Sullivan's work has generally been seen as an improvement over the 49ers' play at the position in recent years, there are two troubling aspects of his first six games. O'Sullivan has been abysmal in the fourth quarter and on third downs.

O'Sullivan ranks 37th in the league with a 48.1 passer rating in the fourth quarter. He has completed just 48.9 percent of his fourth-quarter passes (23 of 47) with two touchdowns and four interceptions.

His passer rating of 54.2 on third downs ranks him 26th in the league.

Yet 49ers coach Mike Nolan has given O'Sullivan a vote of confidence, saying there are no plans to move backup Shaun Hill into the starting role.

O'Sullivan and the 49ers offense seemed to be able to keep the Philadelphia Eagles defense off-balance through the first three quarters of last week's game. The 49ers rolled up 308 total yards through three quarters. The 49ers did not surrender a sack.

"I think our guys were just doing a good job of handling it," O'Sullivan said. "Whether it be pass protecting, blocking them or getting the ball out on hots, and having wide receivers making good plays on the ball."

But things fell apart in the fourth quarter. The 49ers ran 16 offensive plays for minus-two yards. They finished with 306 yards of total offense. The 49ers had six offensive possessions in the fourth quarter; they committed three turnovers and recorded just one first down.

"(It was) a combination of things," O'Sullivan said. "Obviously, the turnovers, but the negative plays, too. It was a handful of things that went wrong."

The 49ers rank 31st in the league in third-down efficiency. Overall, O'Sullivan's numbers are not bad. He has completed 58.2 percent of his passes with seven touchdowns and eight interceptions. His passer rating is 76.4, ranking him 20th in the NFL.