UTG is a 23/16/2.1 reg. I've seen him around but we don't have any history. SB is an unknown shortstack, just joined the table. BB is another regular, 19/15/3.3, again no history.

Nonstandard line for me. Thoughts on flop and turn?

Full Tilt Poker - No Limit Holdem Ring game - Blinds: $5/$10 - 6 players - Converter

Stack sizes:
UTG: $1000
UTG+1: $265.50
Hero: $1272.75
Button: $1530
SB: $384
BB: $1163

Pre-flop: (6 players) Hero is CO with A 5
UTG raises to $35, UTG+1 folds, Hero calls, Button folds, SB calls, BB calls.

Flop: 8 4 4 ($140, 4 players)
SB checks, BB checks, UTG checks, Hero checks.

Turn: A ($140, 4 players)
SB checks, BB checks, UTG bets $90, Hero calls, 2 folds.

River: 9 ($320, 2 players)
UTG bets $210, Hero raises all-in $1147.75