The Bucs begin their exhibition schedule Saturday night against the Cleveland Browns, and the sixth-year pro is bracing for a visit from the boo-birds.
Cleveland can afford to be patient with the development of No. 1 draft pick Tim Couch, however Tampa Bay fans want results from their quarterback now.
Even Dilfer concedes this could be the most important season of his career because the Bucs face a decision on whether to exercise an option on his contract for 2000.
Nevertheless, he insists he isn't looking over his shoulder at backup Eric Zeier.
"I'm going to say this carefully," said Dilfer, who will start and probably take 15-20 snaps against the Browns. "I know what I can do. I proved it. There are things I still have to prove, but every time I step on the field I don't feel like I have to go show people that I can be a productive quarterback in the National Football League.
"I was in the Pro Bowl two years ago, I won a playoff game. Do I still have a million goals to achieve? Absolutely. But it's not like I'm trying to win a spot."
While Couch was impressive in his debut against Dallas in the Hall of Fame game, Dilfer is coming off a poor performance at Miami in a controlled scrimmage that caught the attention of more fans than usual because it was televised live.
Dilfer, whose streak of 64 consecutive regular-season starts is the second longest in the league for a quarterback, said he's not overly concerned about the outing because his mistakes can be corrected easily.
"Playing quarterback, a lot of it is feel. You lose your feel for six months," Dilfer said. "My mind works faster than my instincts in training camp. It takes a couple of weeks for them to catch up. That's where I'm at, and I know how to fix it."
Zeier, a former Brown obtained from Baltimore in a draft day trade, and rookie Shaun King will share the remainder of playing time for the Bucs.
While Dilfer is the unquestioned starter, coach Tony Dungy said it would be a mistake to assume one of the backups can't win the job.
"It's not just necessarily Trent playing himself out of it. Somebody has to be playing better, and that's the bottom line. Who's playing the best? Who gives us the best chance to win? That guy will be the quarterback," Dungy said.
"I think if you're a coach, and you don't play the best people, you're sending a message to your team. You can't do that."
The Browns marked their return to the NFL with a 20-17 overtime victory over the Cowboys as Couch completed 11 of 17 passes for 137 yards ad a touchdown.
Starter Ty Detmer was hoping for more snaps against the Bucs than he got Monday night, however Browns coach Chris Palmer feels it's more important to give Couch as much playing time as possible.
"Ty will play the first series, then we'll get Tim in and go from there," Palmer said.
Couch, who rested a tired arm Thursday and Friday, said the Bucs may pose a tougher challenge than the second-team Cowboys defense he faced.
"They give a lot of different looks, a lot of different blitzes," he said. "If I can go out and handle their blitzes and get us in the right protections in this game, that would be a big step forward for me."