KANSAS CITY, Mo. -- The Chiefs took advantage of the 49ers’ eagerness at inside linebacker in the first half Sunday with some misdirection plays.
It was a rough opening game for the 49ers’ young linebacker duo of Reuben Foster and Fred Warner, but chalk it up to a learning experience in the 49ers’ 38-27 loss at Arrowhead Stadium.
Foster was encouraged with how he and Warner played together and seemed to improve as the team progressed.
“It went well,” Foster said. “It’s like me and Fred never missed a game together, like we’ve been playing together since high school or middle school. It felt amazing with him next to me, calling the plays out.”
The 49ers expect Warner and Foster to line up side-by-side for years to come. Foster was a first-round draft pick last year. He returned to action Sunday after serving a two-game suspension. Warner has started every game at middle linebacker since arriving this year as a third-round pick from BYU.
Veteran Malcolm Smith made his 49ers debut Sunday, and the natural inside linebacker lined up outside in the team’s base defense. Smith played 34 snaps, as Kansas City’s multi-receiver personnel groupings dictated the 49ers deploy their nickel defense for most of the game.
Warner registered a game-high 11 tackles, and Foster was credited with seven. Smith had one tackle and a quarterback hurry.
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The 49ers were flagged for 14 penalties totaling 147 yards, but some of the bigger calls came with plenty of questions about referee Tony Corrente’s crew.
On a third-and-16 from the 49ers’ 32-yard line, nickel back K’Waun Williams was called for pass interference in the end zone against Chris Conley on a Patrick Mahomes pass that did not appear catchable. Instead of a long field goal attempt, the Chiefs had a first down at the 1, and scored on the next play.
C.J. Beathard took one snap and found tight end George Kittle in the end zone for what appeared to be a 7-yard touchdown in the fourth quarter. If the touchdown had stood, the 49ers would have trailed by a touchdown with five minutes remaining.
But fullback Kyle Juszczyk, who lined up as a wideout on the right side, was flagged for a pass interference when Chiefs linebacker Dee Ford stepped in front of him to cut off his in-breaking route. Kittle made the catch behind where Juszczyk and Ford came together.
“I was shocked, actually,” 49ers coach Kyle Shanahan said. “I thought we were going to get a call there, so I was real surprised our fullback got a call of pass interference.”
FOX analyst Dean Blandino, the former head of NFL officiating, even criticized the call on the TV broadcast.
"This is not a pick play," Blandino said. "This is a flag that really should not have been called."
Grounds for a comeback
The 49ers fell behind by four touchdowns before scoring 17 unanswered to get back in the game in the second half. The defense finally made some stops, but the offense got going because it did not give up on the run game.
“I think we just focused on the run,” Kittle said. “We didn’t say, ‘Hey, we have to air it out now because we’re losing by 28 points.’ “
Matt Breida led the 49ers with 90 yards on 10 carries, and Alfred Morris added 67 yards on 14 rushing attempts.
“Whenever you can run the ball, it opens up the passing game,” Kittle said.
Quarterback Jimmy Garoppolo’s expected season-ending knee injury was the most serious, but it wasn't the only injury the 49ers sustained Sunday.
Safety Adrian Colbert appeared in 28 plays before leaving the game in the second quarter with a hip injury. Rookie D.J. Reed replaced Colbert and played the final 52 snaps of the game.
Cornerback Richard Sherman is scheduled to undergo an MRI on his left calf area. He left the game after playing 36 snaps. Ahkello Witherspoon, who has been battling an ankle injury, replaced him.
Cornerback Jimmy Ward left the game because of cramps. In the five snaps he missed, rookie Tarvarius Moore filled in.
Foster took a shot to the midsection and missed one play.
Breida appeared to hyperextend his knee, but he came back into the game and played well.
Defensive lineman Solomon Thomas also was shaken up after colliding with teammate DeForest Buckner while hitting Mahomes. He left the game briefly.
Right guard Mike Person aggravated a foot injury and left the game for seven plays, replaced by Erik Magnuson.
This ‘n’ that
Antone Exum started at strong safety in place of Jaquiski Tartt, who was out with a shoulder injury. Exum recorded nine tackles, his first career sack and a forced fumble. . .
Defensive lineman Arik Armstead was credited with a sack when Mahomes ran out of bounds in the second quarter. It was Armstead’s first sack of the season and the seventh of his career. . .
Kicker Robbie Gould extended his own club-record streak with field goals of 39 and 35 yards, giving him 31 consecutive successful attempts. Gould has made at least one field goal in 23 consecutive games, dating to Dec. 11, 2016. However, Gould missed an extra-point try in the third quarter.