After tweaking, ‘Boston’ is back

It’s a new school year on Fox’s “Boston Public,” and along with the changing fall colors of the New England foliage, there have been seasonal changes in the cast as well.

Executive producer David E. Kelley, whose fine-tuning skills on such ensemble dramas as “L.A. Law” and “Picket Fences” are legendary, is tinkering with the chemistry on the third-year series, not only giving it an injection of new blood, but also young blood.

Joey McIntyre, the former New Kids on the Block heartthrob, has joined the high school’s faculty as Colin Flynn, who could pass for the kid brother of some of his students. Ditto new science instructor Zach Fisher, played by Jon Abrahams (“Scary Movie”). These two spent most of last week’s season debut as window dressing, but in tonight’s episode airing at 8, they share a memorable scene while bar-hopping with colleagues. Who would have thought that NKOTB’s little Joey would one day be warbling “To All the Girls I Loved Before” on a karaoke stage?

Other additions include China Shavers (“Boston Public”) as student Brooke Harper, who also happens to be the principal’s daughter; and Cara DeLizia (“So Weird”) as student aide Marcie Kendall.

Despite all the changes, most of the show’s mainstays remain front and center: gruff but caring principal Steven Harper (Chi McBride); brooding and borderline-boring teacher Harry Senate (Nicky Katt); and Senate’s smoldering lawyer-turned-teacher gal pal Ronnie Cooke (Jeri Ryan).

Though some of the faces are new this season, it’s the same urban high school setting, which means that plot lines about drugs, sex and violence are evergreens.