Sullivan: Bucs need 'perfect execution' to convert third downs

TAMPA — The Bucs' 32 percent conversion rate on third down is the worst in the league, and offensive coordinator Mike Sullivan said Wednesday that the offense requires close to perfection to move the chains.

"Right now, the margin for error is so small for us if we have a less than an ideal play-call, if we have less than perfect execution," said Sullivan, whose unit went 1-for-10 Sunday against the 49ers, the conversion coming on third and 1.

"When we're struggling, it's tough to overcome a dropped pass. It's tough to overcome a sack or a pressure. It's tough to overcome a call where there's anticipation of a coverage and it's there and … they just happen to take away certain things that you're expecting."

Tampa Bay is 6-for-35 (17.1 percent) on third downs over its past three games and hasn't converted a third down of 5 yards or longer in the second half of the past six games, a span of 25 attempts.

On third downs requiring 8 or more yards, the Bucs have just one conversion over their past 34 opportunities, a span six games. Rookie QB Mike Glennon said the key is getting into third downs of 4 yards or fewer.

"In the NFL, when you get in third-and-long situations, it's almost impossible to get that first down," Glennon said. "I think the biggest thing is for us to stay on schedule; to get in third and 4 or less."

The Bucs allowed San Francisco to convert 6 of 15 third downs (40 percent), including ones needing 8, 12 and 15 yards.

NO COMMENT: Sullivan, reported by foxsports.com to interview for the coaching opening at Army, his alma mater, declined to comment. He added it would be inappropriate to talk about potential jobs, "especially given where we're at offensively."

PRO BOWL VOTING: Lavonte David continues to rise in the fan voting for the Pro Bowl, moving up to fifth among outside linebackers with 161,227 votes, in data released Wednesday. The only other Bucs among the top 10 are CB Darrelle Revis, (10th with 167,780) and SS Mark Barron (10th with 56,373). Fans can vote at nfl.com through Dec. 26. The results, also based on votes by coaches and players, will be announced Dec. 27.

INJURY UPDATE: Coach Greg Schiano said Barron (hamstring), WR Vincent Jackson (hamstring), G Davin Joseph (knee) and DE Da'Quan Bowers (knee) were limited at practice.

Meanwhile, Schiano said he was disappointed about WR Russell Shepard going on injured reserve Tuesday for a toe injury sustained Sunday.

"He's really been a critical special teams player for us," said Schiano, noting Shepard played on the kickoff, kickoff return, punt coverage and punt return units. "That will be a big loss. We'll have to have someone step up there or someones."