Briefly:

• Topher Grace will join Jesse Eisenberg, Kristen Stewart, Walton Goggins, and Uma Thurman in Nima Nourizadeh's American Ultra
• Scott Caan is replacing Shia LaBeouf in Barry Levinson's comedy Rock the Kasbah starring Bill Murray, Bruce Willis, Zooey Deschanel, Kate Hudson, and Danny McBride
• Saoirse Ronan will star in John Crowley's Brooklyn alongside Domhnall Gleeson, Jim Broadbent, Emory Cohen, and Julie Walters

Hit the jump for more.

According to Deadline, Topher Grace has signed on to American Ultra.  Max Landis (Chronicle) wrote the script and Nima Nourizadeh (Project X) will direct.  The story centers "on Eisenberg’s character, a stoner whose small-town life with his live-in girlfriend (Stewart) is upended when his past catches up with him, putting him the crosshairs of a government operation bent on wiping him out."  As for Grace, Deadline says he "will play a hotshot CIA agent who has recently taken on seniority that has gone to his head, and power-hungry he begin a mission to kill a secret government asset."  Presumably, Eisenberg's character is the asset.  As we previously reported, Thurman is playing a government employee who "spearheaded a secret program to create sleeper warriors, and now that someone wants to kill her creation, she will fight back like a momma bear protecting her cub."

All in all, this sounds like it could be a really fun movie, and I'm a big fan of Grace, so I'm glad whenever he signs onto a movie.

Moving on, Shia LaBeouf recently left Barry Levinson's Rock the Kasbah, and now Scott Caan is in talks to take the role.  The movie stars Bill Murray as a has-been rock manager, "who takes his last remaining client on a USO tour of Afghanistan. When Richie finds himself in Kabul, abandoned, penniless and without his passport, he discovers a young girl with an extraordinary voice and manages her through Afghanistan’s version of American Idol, the wildly popular Afghan Star."  Per THR, "Caan will play an ammo-dealing con man, who along with his partner (McBride) hustles Murray in war zone Kabul."

There's definitely some potential here, but Levinson's last comedy, What Just Happened, was a flop critically and commercially, so I'm wary.

Finally, Saoirse Ronan is set to lead Brooklyn.  THR reports that Ronan will play Eilis, "who moves from a small town in Ireland to Brooklyn, where, unlike at home, she has the opportunity for work, for a future and for love, in the form of Italian-American Tony (Cohen).  When a family tragedy brings her back to Ireland, she finds herself absorbed into her old community, with Jim (Gleeson) courting her. As she repeatedly postpones her return to America, Eilis finds herself confronting a choice between two men and two countries."  Rooney Mara was previously set to star, but that was over a year ago.

I like Ronan, but I'm hoping she's not playing her little-girl-lost character yet again.  I'm also concerned about the love triangle, which sounds kind of sappy.