This is extremely hard to tell apart from Dean’s other blue shirts, but this shirt has a single seam at the shoulder, a seam detail down the front breast pockets, and buttons that match the colour of the shirt.
Brand Info: Old Navy
In Malleus Maleficarum (3x09), Dean is possibly wearing this shirt for the entire episode (when not wearing a suit), except for the final scene with Ruby.
In Mystery Spot (3x11), Dean wears this shirt on Tuesday.
In Time Is On My Side (3x15), Dean wears it at the beginning of the episode when they interrogate the demon and Sam brings up the possible hunt.
In It’s The Great Pumpkin, Sam Winchester (4x07), Dean wears it when he is staking out the first victims house and discovers that the cheerleader might be the witch. He wears it until Sam exorcises Samhain.
In Criss Angel Is A Douche Bag (4x12), Dean either wears this shirt or a pitch black one exactly like it after Jeb is hung. He changes out of it before the final scene of the episode when he and Sam try to thank Jay.
In Sex and Violence (4x14), Dean once again either wears this shirt or a pitch black one exactly like it until the Siren is dead (when he is not in a suit or in bed).
In I Believe The Children Are Our Future (5x06), Dean wears it to the hospital to check out the guy who had his teeth pulled and the other strange occurrences in town, he keeps it on while he snacks on ham, but then changes back into a suit. He wears it again at the end of the episode when he and Sam rush over to Jesse’s house to find Castiel.
In The Song Remains The Same (5x13), Dean is wearing it when he wakes up from his dream, and when Cas sends them back in time. He changes out of it after Michael returns him to 2010.
In 99 Problems (5x17), Dean is wearing this shirt when Cas brings the Lutheran minister to the motel and they try to recruit him to kill the Whore of Babylon for them. Dean keeps this shirt on until he takes off on Sam, but changes out of it before seeing Lisa.
In Swan Song (5x22), Dean might be wearing this shirt when he arrives at Lisa’s towards the end of the episode.
In You Can’t Handle the Truth (6x06), Dean wears this shirt after they interview the sister of the first victim. He wears it for the rest of the episode, only briefly taking it off while he eats donuts and coffee in bed and Sam reviews the news footage for evidence.
In Family Matters (6x07), Dean is still wearing this when Sam comes to in the motel room and Cas examines him.
In Mannequin 3: The Reckoning (6x14), Dean is wearing this shirt when he arrives at Lisa’s. He wears it until he reunites with Sam and the ghost is dispatched.
In We Need to Talk about Kevin (8x01), Dean wears this shirt when they travel from Rufus’ cabin to Wisconsin. He changes out of it before they go to see Channing at her university.
In Torn and Frayed (8x10), this MIGHT be the shirt that Dean is wearing when he arrives in Kermit, TX, at the beginning of the episode and has a fight with Sam.
In The Great Escapist (8x21), Dean is wearing this shirt at the beginning of the episode when he brings Sam soup. He wears it thorough their researching in the bunker, but after Sam decides they need to go to Colorado.
In I’m No Angel (9x03), Dean wears this shirt while he and Sam search the internet for signs of where Cas might be.
In Paper Moon (10x04), Dean wears this shirt at the beginning of the episode, when he and Sam are on vacation, and then again later when he and Sam go to check out the barn outside of town and find Kate.