Colts 27, 49ers 7: Ahmad Bradshaw ran for 95 yards and a touchdown to overshadow Trent Richardson's Indianapolis debut, and the Colts defense stifled Colin Kaepernick to upset host San Francisco.

Richardson had 13 carries for 35 yards and a score as the Colts (2-1) racked up 179 yards on the ground against one of the league's best rush defenses. Quarterback Andrew Luck completed 18-of-27 passes for 164 yards and added a 6-yard scoring run.

A week after being trounced by the division rival Seahawks in Seattle, Kaepernick again struggled to create offense. He completed 13-of-27 passes for 150 yards - more than 50 of those coming after the outcome was decided - and added an interception for the 49ers (1-2).

Richardson's 1-yard touchdown run put the Colts up less than four minutes into the game, but the 49ers answered quickly as Kendall Hunter ran it in from 13 yards out. The defenses took over in the middle quarters, with a pair of Adam Vinatieri field goals providing the lone offense.

Luck's scoring scamper with 4:13 remaining provided Indianapolis with some insurance and Bradshaw capped the rout with a 1-yard plunge just 1:18 later.

GAME NOTEBOOK: The 49ers announced after the game that LB Aldon Smith was placed on "indefinite leave" to seek treatment in the wake of his arrest Friday on suspicion of driving under the influence and marijuana possession. Smith has already been ruled out of Thursday's game versus St. Louis. ... Luck still hasn't lost consecutive games in his NFL career. ... The 49ers have dropped two in a row for the first time under head coach Jim Harbaugh. They had been 7-0 in games following a defeat. ... Frank Gore led the San Francisco rush attack with 11 carries for 82 yards.