Philadelphia, PA -- (Sports Network) - Come on Baltimore, didn't you learn your lesson from Sammy Sosa?

An aging and injury-scarred former all-star, left for dead in his former city, who is supposed to both revive his career and boost his new franchise's fortunes immediately upon relocation to Charm City - it all has an eerily familiar ring, doesn't it?

The same type of expectation surrounds Steve McNair, the 33-year-old quarterback whose trade from the Tennessee Titans to the Ravens was made official on Thursday, bringing an end to months of speculation.

Impatient Baltimore fans, those that have grown weary of watching the robotic Kyle Boller blunder his way up and down the M&T Bank Stadium turf, have visions of another parade down Pratt Street dancing in their heads.

(An aside: the name "Kyle" is one syllable and pronounced "Kaal" in Baltimore parlance, as in, "You stink, Kaal!" We Baltimoreans did the same to former Orioles catcher Chris Hoiles, who was affectionately referred to as, "You stink, Hools!")

Giddy Ravens supporters see a three-time Pro Bowler and former Super Bowl starter, a tough guy with a rocket arm and legendary mobility, that will make the offense run at its highest level since the franchise was born in 1996. Combined with a defense that remains one of the league's best, some view McNair as the final, crucial piece of the puzzle in the team's re-emergence among the NFL elite.

Here's what I see: Jim Harbaugh. The 34-year-old Harbaugh came to the Ravens in a 1998 trade that inspired similar fanfare, as the QB had led the Colts to a couple of playoff appearances (including a famous near-miss against the Steelers in the 1995 AFC Championship) and had made the Pro Bowl before Indianapolis went into rebuilding mode with some guy named Manning. But the '98 Ravens had problems, not the least of which was head coach Ted Marchibroda, whose best years had come during the silent movie era. Injury difficulties that had plagued Harbaugh in Indy the year before reared their ugly head again, and when healthy he couldn't even manage to keep the immortal Eric Zeier off the field. Harbaugh's one year in Baltimore netted 12 touchdown passes, 11 interceptions, and a 6-10 record that punched both his and Marchibroda's one-way ticket out of town.

McNair is better than Harbaugh, you insist. Probably. But if McNair is in his prime, than so is Enron. Don't tell me about his Pro Bowl appearance last year, which came about only because Carson Palmer, Tom Brady, and Jake Plummer were all hurt. If McNair didn't accept, they were going to call Steve Grogan out of retirement. McNair threw 16 touchdown passes in 2005, two fewer than Gus Frerotte, who should thank his lucky stars that he's still in the league and not coaching quarterbacks at Tulsa.

McNair's last complete season was 2002, and since then his medical chart reads like Estelle Getty's. Knee, finger, calf, ankle, sternum, back, pectoral - if you're wondering why your insurance premiums are high, take a look at the guy wearing the No. 9 jersey. McNair has missed a total of 12 starts over the past three years, and those nagging aches and pains aren't going to go away simply because his TV Guide is being mailed to a different address.

Did anybody see the Ravens' line last year? The right side looked like the turnstile at Grand Central Station so many people passed through unchallenged. Yet the team added zero tackle help via either the draft or free agency, meaning McNair better make sure he's got enough Percocet refills to last the season. He's bound to be hurting.

And that's assuming he picks up coordinator Jim Fassel's offensive system, which will become McNair's third different system in as many years, in short order. And if he adjusts easily to what has to be a traumatizing move for a person who has spent his entire career with one organization. How many examples can you cite of an athlete, in any sport, that plays 11 years with one team before thriving with another the moment he is effectively dumped by the only franchise he's known?

Then there is the issue of the Ravens' chemistry problems, which McNair's presence won't do much to counteract. Ray Lewis is unhappy with Brian Billick, and also cried about the state of the defensive line in the offseason. Jamal Lewis, who showed up only when he felt like it last season, is unhappy with Billick and didn't like the way the team handled his contract situation. The rest of the locker room could give or take both Lewises, and there is major doubt about Billick's hold on the team. Throw a quarterback controversy into this volatile mix and you're probably not going to end up with a group of guys that goes bowling together very often. Bad chemistry and winning rarely go hand in hand.

And do you think the rest of the AFC North is quaking in its collective boots about the prospect of facing McNair, who now becomes only the division's third-best quarterback? The Steelers aren't likely to be a Super Bowl team again but should be able to post double-digit wins. The defending division champ Bengals have the most talent in the North provided Carson Palmer is healthy, and though the Browns think perhaps a little too much of Charlie Frye, Romeo Crennel has overhauled their roster to a point that suggests that the franchise is on the rise. Who are the Ravens, 2-7 on the AFC North road since 2002, going to beat?

The best-case scenario for the Ravens is one or two decent years out of McNair, after which the franchise is going to have to roll the dice by again taking a quarterback early in the draft. Boller, who actually looked to be making strides during the second half of last season, will probably be long gone by then. Maybe sticking with Boller wasn't the answer, but perhaps bringing in someone like a Kerry Collins, who would have been cheaper and might have pushed Boller rather than simply supplanting him, would have been a more prudent option in the long-term. McNair certainly isn't coming to Baltimore to fight for a job, and his presence on the roster means that the fans aren't going to suffer another Boller mistake without demanding an immediate change.

All of which points to a lot more dysfunction, along with some more losing, in the great and proud city of Baltimore.

Just like with Harbaugh, just like with Sosa, this trade represents yet another case of style over substance.