SANTA CLARA One day after wideout Brandon Carswell tore a knee ligament, the 49ers worked out former Indianapolis Colts receiver Austin Collie.
Collie, who starred at Oak Ridge High School, caught passes from rookie quarterback B.J. Daniels for about 15 minutes Thursday as assistant coaches, trainers and scouts looked on.
With Michael Crabtree (Achilles' tendon) out for training camp and Mario Manningham (knee) unlikely to participate, the 49ers are expected to add another receiver before camp begins in late July.
Coach Jim Harbaugh said "there are still a few more things we want to have checked out" before the team makes a decision on Collie, presumably referring to medical clearance. Collie has had three concussions since joining the NFL in 2009, and he tore his patellar tendon early last season with the Colts.
Harbaugh said the workout went well.
"He had a patellar tear 7 1/2 months ago and he's very far along," Harbaugh said.
Asked if he was concerned by Collie's concussions, Harbaugh said, "That's for the doctors to look at and analyze." One of the team's doctors, Daniel Garza, is a specialist in concussions and head injuries at Stanford Hospital.
Collie, 27, had three strong seasons in Indianapolis (2009-2011), but he caught only one pass for six yards last season before his knee injury. He worked out for the New England Patriots earlier this week.
Carswell tore his ACL just minutes into his first practice with the 49ers on Wednesday after signing a contract earlier in the day. He was on the Raiders' practice squad last year.
The 49ers receivers are Anquan Boldin, Chad Hall, Chuck Jacobs, A.J. Jenkins, Ricardo Lockette, Marlon Moore, Kassim Osgood and Quinton Patton.
Kyle Williams and Manningham have been rehabilitating on their own, although Williams has been worked steadily into practices over the past three days and could be available for the start of camp.
Harbaugh downplays giveaway Harbaugh said free-agent acquisition Craig Dahl's disclosure to 49ers coaches that the St. Louis Rams were picking up on cues that told them whether the 49ers were planning to run or pass was a confirmation of what the coaches already knew.
He said it was a problem in the Nov. 11 game but had been corrected by the rematch Dec. 2. Both games went to overtime; the first ended in a tie, the other a Rams win.
Dahl's former teammates were not happy with his revelation, with cornerback Cortland Finnegan calling Dahl "lame and weak" on Twitter.
Et cetera Harbaugh said 31 players earned perfect-attendance certificates for being at every meeting, workout and practice of the spring practice sessions. Harbaugh passed out those certificates and T-shirts after Thursday's practice, which marked the end of the the team's three-day minicamp.
Although veterans are dismissed until training camp, the 49ers can work rookies for the next seven days.
Williams, who tore his ACL on Nov. 25, was one of several players who returned punts Thursday. He also sprinted full lengths of the field and appears close to full strength.