Following Sunday's 20-10 loss to the Arizona Cardinals, San Francisco 49ers head coach Kyle Shanahan believed that the injury to Jaquiski Tartt was a serious one.

"Tartt, I think, broke his arm, so I think it's going to be similar to what happened to Jimmie [Ward]," Shanahan told reporters. "I'd be surprised if he doesn't go on IR."

Tartt was officially placed on injured reserve on Monday evening. He played well for the 49ers this season. Tartt was ranked as the 11th-highest graded safety according to Pro Football Focus.

Tartt was a second-round draft pick by the 49ers in 2015. He has started all nine games for the 49ers this season and registered 55 total tackles, an interception, and three passes defensed. In three NFL seasons, Tartt has recorded 181 total tackles, 3.5 sacks, nine passes defensed, and two interceptions in 39 games and 23 starts.

The 49ers also placed rookie tight end Cole Hikutini on the team's growing injured reserve list. He suffered an MCL injury on Sunday against the Cardinals.

Hikutini was originally signed by the team as an undrafted rookie free agent on May 4. He was waived on September 2 during roster cut-downs and signed to the team's practice squad the following day. The 49ers promoted Hikutini to the active roster on October 14.

Hikutini, 23, played college football at the University of Louisville where he appeared in 24 games and started 13. During his two-year career with the Cardinals, he tallied 69 receptions for 1,016 yards and 11 touchdowns. In 2016, Hikutini appeared in 13 games, started 10, and caught 49 passes for 656 yards and eight touchdowns. He transferred to Louisville after spending the 2014 season at the City College of San Francisco.

Hikutini has appeared in four games for the 49ers this season and registered two receptions for 15 yards.

The 49ers used the vacant roster spots to officially sign wide receiver Louis Murphy and tight end Logan Paulsen. Both Murphy and Paulsen have spent time on the 49ers roster in 2017. Murphy signed with the 49ers on July 31 and was later waived on September 1. Paulsen appeared in each of the team's first seven games this season and was released on October 24.

The 49ers also signed offensive lineman Andrew Lauderdale to the practice squad. He originally signed with the team as an undrafted free agent on June 9 and was later waived on September 1.