Could history be repeating itself? The Detroit Pistons sure hope so.

For the second year in a row, the Pistons have embarked on a lengthy February winning streak after sleepwalking through the first half of the season. A year ago, they won 20 of their final 24 regular season games by a gargantuan average of 13.1 points per game, and rode that wave all the way to the NBA title. This winter, the Pistons have won 12 of their last 13 games by a mouth-dropping average victory margin of 14 points per game.

The catalyst last season was a pair of trades that General Manager Joe Dumars executed at the trade deadline, netting Rasheed Wallace and Mike James. Those two proved to be

the missing pieces, as Wallace cemented a withering defensive attack and James solidified the guard position behind Chauncey Billups. This season, Dumars pulled off another important midseason trade, acquiring point guard Carlos Arroyo from Utah in return for a future first-round pick. Once again, the Pistons subsequently became a terror.

But let’s not anticipate an encore performance in the postseason. The differences between the 2004 and 2005 Pistons are at least as important as the similarities. The biggest one is the bench. Last season, when a starter was struggling or facing foul trouble, coach Larry Brown could turn to one of the league’s deepest benches. With James, Corliss Williamson, Mehmet Okur, Lindsey Hunter, and Elden Campbell, his crew rivaled some teams’ starting five.

Obviously, Detroit’s starting five of Ben Wallace, Rasheed Wallace, Tayshaun Prince, Richard Hamilton, and Finals MVP Billups was the most important part of the championship run. But in playoff series against top-heavy teams like the Nets and the Lakers, it was Detroit’s bench that was the difference maker.

This year, they’re not around to make a difference. Only Hunter returns from that group – and he was the worst of the five. Joining him are just two quality reserves: Antonio McDyess (reborn as soon as he left the Knicks, naturally) and the recently acquired Arroyo. That gives Detroit a passable eight-man rotation, but things get ugly after that. Ronald Dupree has been predictably deficient when pressed into service as a backup small forward, while rookie Carlos Delfino was hardly better before he got hurt.

Detroit’s second unit has let the team down several times this year, especially in comparison to the lift the Pistons often got a year ago. If we compare the two units using my Player Efficiency Rating, a measure of each player’s per-minute statistical performance, it’s easy to see how Detroit’s reserves are falling short this year.

Even the Pistons’ better bench players struggle to compare favorably to last year’s group. Okur was outstanding a year ago, so McDyess’s above-average play isn’t an improvement. Arroyo solidifies what had been a black hole behind Billups, but still falls short of the value James provided a year ago. While Hunter has been slightly more effective as the backup shooting guard than he was last season, that’s not enough to offset the Pistons’ glaring weaknesses in the frontcourt, where the spots previously held by Williamson and Campbell now belong to D-League talents Dupree and Darvin Ham.

To his credit, Dumars is working to solve the problem, but his options are dwindling now that the trade deadline has passed. Detroit is working to add another big man, with temporary Hornet Dale Davis a likely candidate. When New Orleans releases him – a foregone conclusion – the Pistons will be fighting Indiana for his rights. However, even the addition of Davis (10.6 PER) won’t pull Detroit up to last year’s level.

That’s not the only reason to be dubious of the Pistons’ recent hot streak. Their enlivened play of late hasn’t exactly come against a Murderer’s Row of opponents. Only five of their 12 victims have winning records, and three of those five suited up against Detroit without their best player. Additionally, the one loss was a 22-point drubbing against the Nets, whom even diehard supporters must admit aren’t likely to be challenging for the Larry O’Brien Trophy this June.

The real test will come this month. Detroit is in the midst of a grueling six-game West Coast swing that finishes with dates at Phoenix, Seattle, and Sacramento. Later in March, the Pistons face home games against Seattle, Sacramento, San Antonio, and Dallas and road dates against Cleveland and Chris Webber’s Sixers.

But here’s the biggest reason to doubt the Pistons: They’ve been perfectly healthy and still haven’t managed to distance themselves from the pack. Detroit’s five starters have missed a total of 12 games this year, with half coming during Ben Wallace’s six-game suspension after the Malice at Auburn Hills. The team’s fortunes could plunge if one of them gets hurt – if McDyess or Arroyo move up into the starting lineup, it opens a hole behind them that the Pistons are unable to fill.

That doesn’t mean the Pistons can safely be ignored. As long as all five starters remain healthy, Detroit should hang on to the second seed in the Eastern Conference. In a short playoff series, perhaps they can even paper over the weaknesses on the bench to put a scare into the Heat in the Eastern Conference finals.

But this team began the year hoping to defend its title, and the current group still doesn’t look capable of doing that. The Pistons’ recent run of success is impressive, but it’s come against the dregs of the league rather than its cream. Unless Dumars can find some magic potion that converts Ronald Dupree into Corliss Williamson (and some people wouldn’t put it past him given what he’s accomplished in Detroit), the Pistons’ chances at repeating are looking slim.

Instead, imagine something more like what the Nets did a year ago. The two-time conference champions put up a tough fight, but ultimately they were undone when the reserves couldn’t provide the extra boost they needed to get them past a tough opponent. The Nets were vanquished by Detroit, ironically enough, in the toughest test the Pistons faced en route to the title. This year the shoe is on the other foot as the Pistons are the ones lacking in depth – which Detroit will desperately need to combat Shaq and the Heat in the conference finals. So in a way, history will repeat itself. Just not in the way Detroit had hoped.