The NFL will determine whether San Francisco 49ers quarterback Colin Kaepernick was justifiably penalized and actually directed inappropriate language toward a Chicago Bears opponent in the 49ers' Sunday night loss, according to a league source.

Colin Kaepernick insists he didn't say anything to warrant the flag he was issued Sunday night. AP Photo/Tony Avelar

The NFL will look into the situation during its weekly video review of officiating Tuesday.

"I didn't say anything," Kaepernick said after the 28-20 loss to the Bears, in which he threw three interceptions and lost a fumble. He drew an unsportsmanlike conduct penalty for "inappropriate language" late in the game.

Coach Jim Harbaugh said he didn't overhear anything from the sideline that would warrant a penalty.

Harbaugh reiterated in his Monday media conference that he did not receive an explanation about the penalty, which fueled speculation that a racial epithet was heard, and said he still wants clarification from the league on the call.

"Yeah, we'd like that," Harbaugh said. "Find out about that."

The 49ers were flagged for 16 penalties Sunday night -- a single-game high under Harbaugh and tied for the second-most in the NFL since 2011.

ESPN.com 49ers reporter Paul Gutierrez contributed to this report.