TAMPA, Fla. — Winning, and gaining that highly sought-after momentum for the playoffs, came at a steep price for the Seahawks on Sunday as they beat the Tampa Bay Buccaneers 23-7.

Seattle, which will open the playoffs with a wild-card game against the Dallas Cowboys on Saturday at 5 p.m. at Qwest Field, will likely be without three of their top four cornerbacks after Kelly Herndon and reserve cornerback Jimmy Williams joined Marcus Trufant on the sideline with leg injuries.

The injuries took some luster off a game the Seahawks won convincingly and expectedly, casting aside the listless Buccaneers at Raymond James Stadium. Quarterback Matt Hasselbeck put it all together for his best game in his past three starts, completing 17 of 29 passes for 216 yards and a touchdown.

Hasselbeck wasn't alone.

Shaun Alexander rushed for 92 yards and a score. D.J. Hackett came up big once again with four catches — one for a touchdown — and tight end Jerramy Stevens shone with four catches for 54 yards. The difference in the game, Hasselbeck said afterward, was the Seahawks' final drive of the third quarter that extended into the fourth: A 14-play, 65-yard drive for a field goal that saw the Seahawks run the ball 10 times and run 8 minutes, 12 seconds off the game clock.

Defensively, Lofa Tatupu led a unit that gave up a few big plays but made more than it allowed in shutting out the Bucs in the second half. The group gave up just 15 rushing yards in the second half.

But there was a major downside to it all. The Seahawks (9-7) are facing the possibility of not having either of their starting cornerbacks because of injury when they play the Cowboys in the NFC wild-card round.

In fact, Seattle will almost certainly be without three of their top four cornerbacks on the depth chart. Marcus Trufant, a starter, won't play Saturday unless his high right ankle sprain miraculously heals. He missed Sunday's game.

During the game, the Seahawks lost starting left cornerback Kelly Herndon to a broken left ankle near the end of the first quarter.

The injury looked ugly on replay, as Bucs receiver Joey Galloway and Herndon went up for what was a 44-yard catch for Galloway. Herndon landed awkwardly on his ankle and it bent inward as he tumbled to the grass.

Herndon had to be helped off the field and was later carted to the locker room for X-rays. He left the stadium on crutches and needed another cart to get to the team bus after the game.

That left the Seahawks with rookie Kelly Jennings and seldom-used reserve Jimmy Williams at cornerback. Both had been situational and special-teams players this season.

The exuberant Williams recovered a fumble in the third quarter that set up a Seahawks field goal and 20-7 lead, and spiked the ball as he ran off the field. But he needed help to leave the field early in the fourth quarter. After a pass play, on which Williams wasn't in on the tackle, Williams remained on the ground and had to be helped off.

He, too, was taken to the locker room. Williams is scheduled to undergo an MRI to determine the exact nature of his injury.

Jordan Babineaux, a nickel cornerback in 2005 who started eight games at safety this season, stepped in and played cornerback. It appears it will be Babineaux and Jennings against the Cowboys' arsenal of receivers Saturday.

That's Terrell Owens, a Qwest Field arch-enemy for his Sharpie incident in 2002; speedy Terry Glenn and the dangerous Patrick Crayton.

"If you ask for volunteers, there's not a lot of guys left in that section of the plane," Holmgren said when asked if he anticipates having to go with Jennings and Babineaux. "We have those guys, and we're working on maybe bringing a couple of guys in, but at this stage of the season it's difficult. You just do what you have to do."

The Seahawks signed cornerback Rich Gardner last week for depth, though he didn't play Sunday. They also have Gerard Ross on the practice squad as an option. As of Sunday night, that was it as far as possible reserves on hand.

"Knowing our situation, that we're short-handed, it's to the wall now," Babineaux said. "It's lights-out now. We don't have a choice. It's win or go home."

Jennings made his first career start against Tampa Bay and held his own in coverage, never being burned for a big gain.

"It's kind of what I was brought in for, and I just have to step up and play now," Jennings said. "[Starting] helped me prepare for what's at stake."

The win over the Buccaneers meant nothing as far as playoff positioning. Holmgren chose not to rest his starters, preferring that the Seahawks' regulars play it out for the win even though he did rest Alexander in the final minutes.

The Seahawks had hoped to get out of Florida injury-free with a positive, confidence-boosting win to end the regular season.

One out of two happened.

"There's something about 9-7 being a lot better than 8-8, even though it's just one game," Holmgren said. "Now we start our new season."

José Miguel Romero: 206-464-2409 or jromero@seattletimes.com