Even though hip-hop has replaced rock as the predominant force in contemporary music, Best Rock Album remains one of the most crowded and competitive categories on the Grammy ballot. A total of 310 albums are entered for Best Rock Album this year—more than in Best Rap Album, Best R&B Album and Best Country Album combined. Only one other "genre album" category has more than 300 entries—Best Jazz Instrumental Album, with 328 entries.

Let's take a look at the highly competitive races for Best Rock Album and Best Alternative Music Album.

Best Rock Album

The likely nominees

Metallica's Hardwired…to Self-Destruct. The band was nominated in this category for its previous album, Death Magnetic. Metallica teamed with Lady Gaga to perform "Moth into Flame" on the Grammy telecast in February.

Leonard Cohen's You Want It Darker. Cohen's final studio album got rave reviews. It has a commanding 92 score at Metacritic.com.

Foo Fighters' Concrete and Gold. The group failed to receive a nomination for its previous studio album, Sonic Highways, but it was nominated for each of its six albums before that. (Four of those albums won.) If the Foos land a seventh nom this year, they'll tie Neil Young for the most noms in the history of the category (which dates to 1994). "Run" was up for Best Rock Video at the VMAs.

Green Day's Revolution Radio. The group wasn't nominated for ¡Uno!, ¡Dos! or ¡Tré!, but American Idiot and 21st Century Breakdown, its two albums before that trilogy, both won in this category. "Bang Bang" and "Still Breathing" were #1 alternative songs. "Bang Bang" was up for Best Rock Video at the VMAs.

Harry Styles' Harry Styles. The One Direction alum has yet to be nominated for a Grammy—though that will likely change on Tuesday. This album has a good shot at an Album of the Year nom. "Sign of the Times" is likely to be nominated for either Record or Song of the Year. (I say Record. My fellow Grammy Nerd Lenny Beer says Song). There will likely be some debate about whether the Grammys put this album in the right genre album category. "Sign of the Times" was up for Best Pop Video at the VMAs.

Other strong contenders

Highly Suspect's The Boy Who Died Wolf. The band was nominated in this category for its previous album, Mister Asylum. And this album charted significantly higher.

Brand New's Science Fiction. This album debuted at #1, to the surprise of many. It has an impressive 88 score at Metacritic.com.

Kings of Leon's WALLS. The band's last three studio albums were nominated in this category. "Waste a Moment" was a #1 alternative song.

Dan Auerbach's Waiting on a Song. El Camino and Turn Blue, Auerbach's last two studio albums with The Black Keys, were both nominated in this category. (El Camino won.) This album was just a modest hit, which may hurt its chances.

The Killers' Wonderful Wonderful. The Killers were nominated in this category 13 years ago for Hot Fuss, but their last three studio albums were passed over. Wonderful Wonderful, co-produced by Jacknife Lee, was the band's first #1 album. It could put them back in the running.

The War on Drugs' A Deeper Understanding. This was the band's first top 10 album.

Ryan Adams' Prisoner. Adams' last studio album of original material, Ryan Adams, was nominated in this category.

Queens of the Stone Age's Villains. The band was nominated in this category for its previous album, …Like Clockwork. This album didn't chart quite as high.

Cage the Elephant's Unpeeled. The group won in this category last year with Tell Me I'm Pretty. This live album was just a modest hit.

Linkin Park's One More Light. The band was nominated in this category 16 years ago for its debut album, Hybrid Theory. The death of lead singer Chester Bennington in July will put extra focus on this album.

Blackberry Smoke's Like an Arrow. This was a #1 country album. It's not every day you see a #1 country album vying for a Best Rock Album nom.

Also possible: John Mayer's The Search for Everything, Sting's 57th and 9th, Sheryl Crow's Be Myself, Lindsey Buckingham/Christine McVie's Lindsey Buckingham & Christine McVie, AFI's AFI (The Blood Album), All Time Low's Last Young Renegade, Alter Bridge's The Last Hero, Avenged Sevenfold's The Stage, Bon Jovi's This House Is Not for Sale, Depeche Mode's Spirit, Dropkick Murphys' 11 Short Stories of Pain & Glory, Incubus' 8, Mastodon's Emperor of Sand, Neck Deep's The Peace and the Panic, Rise Against's Wolves, Stone Sour's Hydrograd, 311's Mosaic, Kate Bush's Before the Dawn, Disturbed's Live at Red Rocks, Roger Waters' Is This The Life We Really Want?

Notes: Several key albums that straddle the line between pop and rock are competing for Best Pop Vocal Album rather than Best Rock Album. Among them: Imagine Dragons' Evolve, Paramore's After Laughter, Lorde's Melodrama, Lana Del Rey's Lust for Life and Portugal. The Man's Woodstock. Did the Grammys make the right calls in these borderline cases? You decide.

For the record, the number of entries in this category this year (310) is down from 342 last year.

Best Alternative Music Album

The likely nominees

Arcade Fire's Everything Now. The band's four previous studio albums were all nominated in this category. (None of them won, even though The Suburbs won the big one—Album of the Year.)

The National's Sleep Well Beast. The group's previous studio album, Trouble Will Find Me, was nominated in this category four years ago.

Father John Misty's Pure Comedy. As a member of Fleet Foxes, Josh Tillman (a.k.a. Father John Misty) was nominated for Best Folk Album of 2011 for Helplessness Blues.

The xx's I See You. This album debuted at No. 2, becoming the group's highest-charting album to date.

LCD Soundsystem's American Dream. The group's first two albums were nominated for Best Dance/Electronic Album.

Other strong contenders

alt-J's Relaxer. The group's previous album, This Is All Yours, was nominated in this category three years ago. (This album didn't chart quite as high.)

Gorillaz' Humanz. The virtual group has been nominated in various pop, urban/alternative and rap categories.

Ani DiFranco's Binary. DiFranco has never been nominated in this category, but she has been nominated twice for Best Contemporary Folk Album. This album was just a modest seller.

Nine Inch Nails' Add Violence. The band's previous album, Hesitation Marks, was nominated in this category four years ago. Before that, the band was nominated in this category with The Downward Spiral and The Fragile. But this EP may be at a disadvantage competing with full-length albums.

The Shins' Heartworms. The group's 2007 album, Wincing the Night Away, was nominated in this category. A subsequent album was passed over.

Phoenix's Ti Amo. The group won in this category eight years ago with Wolfgang Amadeus Phoenix. A subsequent album was passed over.

Feist's Pleasure. Her 2007 album The Reminder was nominated for Best Pop Vocal Album.

Also possible: The Flaming Lips' Oczy Mlody, Phantogram's Three, Spoon's Hot Thoughts, Grizzly Bear's Painted Ruins, Kid Cudi's Passion, Pain & Demon Slayin', Thurston Moore's Rock N Roll Consciousness.

Note: A total of 135 albums were entered in this category, down from 145 last year.