"....Pucey throws to Warrington, Warrington to Montague, Montague back to Pucey - Johnson intervenes, Johnson takes the Quaffle, Johnson to Bell, this looks good - I mean bad - Bell's hit by a Bludger from Goyle of Slytherin and it's Pucey in possession..."
-- Lee Jordan commentating a Gryffindor-Slytherin match (OP19)
Adrian Pucey is a Chaser on the Slytherin Quidditch Team who participated in some of the hardest-fought matches of Harry Potter’s Quidditch career at Hogwarts, including the match where Harry’s arm was shattered by a rogue Bludger (CS10).
Pucey was most likely a year ahead of Harry.
Adrian is derived from the name Hadrian (Hadrianus), meaning "from Hadria" - a person from one of two Roman settlements with that name in Italy (Behind the Name).
Pucey is a variant spelling of the surname Pusey. It is English, from a place originally called Pesei or Puseye in Berkshire. It derives from pisu ("pea") and eg ("an island or low-lying land") (Internet Surname Database).
Since he was on the Slytherin team during Harry's first year (PS11), he was at least a year ahead of Harry; since he was still there during Harry's fifth year (OP19), he's no more than two years ahead of Harry, assuming he's up to scratch academically.
Lexicon list of Chasers
From the Web
Harry Potter Wiki: Adrian Pucey