I heard this was a Locke episode. So, by the end of the season only Claire and Sawyer won't have had episodes centering on their characters? I wonder if these were the two from the 16 that were cut as a result of the strike.

It's a flashBACK, not a flashforward

Episode 4.11: Cabin Fever (Locke-centric)
Airdate: May 8, 2008

* 04/21 - Locke is enlightened as to the whereabouts of Jacob's cabin, and life aboard the freighter becomes perilous. Guest starring are Jeff Fahey as Frank Lapidus, Lance Reddick as Matthew Abaddon, Marc Vann as doctor, Kevin Durand as Keamy, Anthony Azizi as Omar, Grant Bowler as Captain Gault, John Terry as Christian Shephard, Holland Roden as Emily, Rebecca Tilney as Emily's mother, Amanda Carlin as ER nurse, Patrick Torres as ER doctor, Doug Hutchison as Horace Goodspeed, Nestor Carbonell as Richard Alpert, Matthew Pedersen as physical therapist, Mandy June Turpin as Florence, Sarah Duval as Melissa, Charles Henry Wyson as John Locke (age 5), Phil Abrams as Gellert and Caleb Steinmeyer as John Locke (age 16). Source: ABC
* 04/06 - The Lost production team is working double-time to deliver the last five episodes of Season 4. Thursday found them working all over the island for Episode 4.11, a Locke-centric outing. In the morning, they finished up at Waimano Home in Pearl City, with Terry O'Quinn and Lance Reddick on the scene. At the same time, a second unit was at work at Manoa Falls Trail, filming an on-island scene. Emilie DeRavin, Josh Holloway, Daniel Dae Kim, Yunjin Kim, Rebecca Mader and Jeremy Davies trekked through the jungle past a simple wooden Dharma door. After lunch, the action moved to Leilehua High School in Wahiawa. Students and cheerleaders in 1960s garb brought us to Cowan Heights (near Tustin, CA) to witness Locke's struggles at sixteen. It looks like our "Man of Faith" has had issues with science for a long, long time. [...] Late word from Wahiawa United Methodist Church, reporting several "gorgeous" 1950s or 1960s cars. And one of them was apparently enlisted to film a dramatic scene in which a little girl (perhaps five years of age) runs out of a house and gets struck in the street. Source: The Transmission
* 04/06 - They filmed at Leilehua High School today (04/03/08). There was a high school logo that said "Cowin Heights Knights." [They filmed] some kid coming out of a locker. Source: Lost Spoilers
* 04/03 - Waimano Home is a former mental institution turned government office and laboratory hidden high in the mountains above Pearl City in Leeward O'ahu. Its drab, concrete walls and stark halls made it the perfect location to shoot a hospital scene. The wardrobe suggests that we'll be visiting the 1950s, and possibly another decade in the past. The where and the when, though, is nowhere near as interesting as the who. The flashback revolves around John Locke (Terry O'Quinn), and it's a flashback to the very beginning of his story: his birth. We'll also see Emily, his mother, in her younger days (presumably before her time in Santa Rosa, and before she betrays John Locke for his father's kidney hunt). But someone else is wandering the hospital: the ageless and eerie Richard Alpert, looking quite dapper in a suit. Source: The Transmission
* 03/30 - Mother - Caucasian, late 30s, with red hair and blue or green eyes, Frazzled, annoyed, trying to keep her daughter under control and tired of dealing with her when she seems to only make one bad decision after the other. Gellert - Any ethnicity, 30s-40s. High school chemistry teacher, intelligent and understanding, he offers a bright student the chance of a lifetime but becomes resentful when the offer is refused. Florence - Any ethnicity, late 30s. A foster mother who is worn out and overwhelmed. She is charmed by an unexpected visitor she anxiously hopes might help her situation, but she turns punitive when it doesn't go well. Susie - Any ethnicity, 30s to 40s. A nurse working the late shift who unexpectedly has to help deliver a baby. Professional and compassionate, she tries to help the mother adjust to her new reality. Source: Lost Spoilers
* 03/17 - Five-year-old Boy - Caucasian, green eyes, sweet, shy, tentative and smart. Has to take a test and becomes nervous about passing. Teenage Boy - Plays as 16 or 17, Caucasian, green eyes. Angry, a little nerdy, defiant and rebellious. There's a lot more to this kid than meets the eye. Tries to fight back against older, stronger boys but is pushed into a locker. Teenage Girl - Plays as 16, Caucasian, red hair (or willing to dye hair red). Emotional, prone to dramatic gestures, passionately in love and fights with her Mom about it. Source: Lost Spoilers

and this is a Locke episode