TAMPA — It comes down to math. Bucs coach Bruce Arians says there are six “generational” players in the NFL draft, and his team picks fifth overall. So, in summation, he says he’s not inclined to trade down.“There would have to be some hellacious picks,’’ Arians said. “There’s five guys on the board I love. You’d have to throw the bank and open the vault for (general manager) Jason (Licht) to move down. I’m not saying that we wouldn’t. Just looking at the guys that are there, there’s really six guys that are once-in-a-generation type players. I’m feeling great about this draft.’’It’s not hard to speculate which six players Arians considers “generational” talents. Most likely they include several defensive players: Ohio State defensive end Nick Bosa, Alabama defensive tackle Quinnen Williams, Kentucky edge rusher Josh Allen, Houston defensive lineman Ed Oliver, Louisiana State linebacker Devin White and perhaps either Michigan linebacker Devin Bush, Oklahoma quarterback Kyler Murray or Mississippi State edge rusher Montez Sweat.“His tape is great,’’ Arians said of Murray. “The only thing I will say is a negative is he’s a one-year player. One-year players have scared me in the past. He is dynamic, and I wouldn’t want to chase him around.''The Bucs’ biggest needs are on defense. With the team seemingly ready to move on from defensive tackle Gerald McCoy, defensive tackle would appear to be a big need. But the Bucs also lost middle linebacker Kwon Alexander to the 49ers in free agency. While the Bucs have no shortage of edge rushers with Jason Pierre-Paul, Carl Nassib, Shaq Barrett and Noah Spence, Arians said you need to draft the best available player regardless of position.“No. Listen. You can’t draft for need,’’ Arians said. “If you draft for need, you get fired. You take the best player. If you’ve got two players, now you’ve got three of them. Just take the best player available. Now if you’ve got four players right there together and one of them is a need? That’s a home run.’’Besides, Arians argues, it’s too easy for teams to double-team the best pass rusher.“You need two because they can game-plan one guy,’’ Arians said. “… You’d like to have two, and I think JPP is that type of guy. Vita (Vea) can be some pressure in the middle. We’ve got a couple of young guys who have the ability to play opposite and be disruptive. And I know our linebackers are going to be blitzing up the middle a lot and they’re going to be chasing him out to them a lot of times. You want guys who can beat the tackles but also run them down when they get outside.’’Arians said it has been easy working with Licht since they went through a draft together with the Arizona Cardinals.“It’s been very easy for both of us because we’ve done it together before,’’ Arians said. “The respect factor is deep. It’s been easy.“We were ready three weeks ago. We’ve been going over and over and over it. Jason and I have massaged that thing so many times it’s got fingerprints all over it.’’Of course, as the draft nears, Arians says, it’s hard to believe anything they hear or read.“I’m never convinced about anything about the draft,’’ he said. “That’s the best thing about it. Everybody lies so good. That’s the best thing. You start telling the truth and it’s, ‘Oh he’s lying. He’s lying!'"