San Francisco 49ers quarterback Colin Kaepernick found a new favorite target in receiver Anquan Boldin.  The recent addition has stepped in to fill the void left by injured receiver Michael Crabtree, NFL.com reports.

When Crabtree went down with an Achilles tear, the 49ers' depth at receiver came into question.  Crabtree enjoyed a breakout season last year, recording his first 1,000-yard season and nine touchdowns.  He became Kaepernick's favorite target.

Now, with Crabtree's season in jeopardy as he recovers from surgery, Boldin has become an OTA favorite for his young quarterback.  NFL.com reports the veteran as stealing the show during a Tuesday practice, catching all 10 passes thrown his way and looking sharp on the field.

"He's really picked up the system fast, and is making plays and big catches in tight areas," 49ers coach Jim Harbaugh told reporters.  "You saw what we've been seeing for a couple weeks now."

Boldin, 32, was acquired by San Francisco in the offseason — months after he and the Baltimore Ravens defeated the 49ers in the Super Bowl.  He joins a receiving corps of A.J Jenkins and Mario Manningham.

While it's too early to tell how effective Boldin will be on the field, the positive report from Tuesday could put a return from Randy Moss in further question.  Harbaugh has already stated his intention of seeing which receivers will emerge in Crabtree's absence.  If Boldin can become a reliable option for Kaepernick, Moss's services could go unneeded.  

Moss, 36, was considered an early possibility to join San Francisco because of his familiarity with the playbook.  He played for Harbaugh last season, but was unsatisfied with his relatively small role in the offense.

Boldin, meanwhile, is eager to win Kaepernick's trust as a go-to-guy.

"He's a special talent.  He can make any throw on the field," Boldin said.  "I want Kaep to be comfortable.  Even if it doesn't look I'm open, give me a chance."