. The 49ers’ second stringers were quicker and more powerful than their counterparts on Friday. The battle between the would-be starters, however, went to the Chiefs.
In his NFL head-coaching debut, Kyle Shanahan watched as Alex Smith and the Chiefs marched 75 yards for a touchdown on their opening drive, largely at the expense of Rashard Robinson, whom the 49ers are counting on to be their top cornerback this season.
Robinson has had trouble keeping pace with receiver Marquise Goodwin in training-camp practices this summer. He had the same issue Friday with speedy Chiefs receiver Tyreek Hill, who caught a 32-yard pass down the sideline against Robinson on the game’s first play.
Robinson later badly missed a tackle on a short pass that brought the Chiefs to the 2-yard line, and they scored on an up-the-gut run on the ensuing snap. He also was in coverage on an 83-yard touchdown on Kansas City’s next possession that was nullified by an offensive pass-interference penalty.
The struggles underscored one of San Francisco’s most glaring weaknesses with the regular season less than a month away: They have very little experience at cornerback and not much depth. The other would-be starter, Dontae Johnson, missed the game due to a concussion and his replacement, Keith Reaser, allowed a 41-yard pass play in the second quarter.
The 49ers offense responded to the Chiefs’ touchdown by going backward — minus-seven yards — on their first offensive drive and gaining five yards on their second. Starting quarterback Brian Hoyer exited the game 1-4 for three yards.
Shanahan emphasized earlier in the week that no one will remember the team’s preseason record and that he didn’t want to waste any clever plays in August.
“You can feel good going 4-0 in the preseason, but I’ve done that before and lost the first game and no one cares what the preseason record was,” Shanahan said.
Instead he said he wanted to focus on foundational plays on which the offense is built. But even those plays — inside and outside zone runs, for example — fizzled. Carlos Hyde had two runs for zero yards and Hoyer couldn’t connect with his top two receivers, Pierre Garcon and Marquise Goodwin. The 49ers committed eight penalties for 65 yards in the first half alone.
Even the special teams stumbled by giving up a blocked field-goal try and a blocked punt.
“We’ve got to clean up the penalties,” Shanahan said at halftime. “Anytime you get in the end zone twice and neither of them count — and a big third down there on our first drive that caused a three-and-out. We’ve got to clean that stuff up before we score.”
Both Robinson and the 49ers’ starting defense bounced back on Kansas City’s second drive when, with Tyler Bray playing quarterback for Kansas City, Robinson intercepted a pass in the flat and returned it 30 yards. Robinson got an assist on the takeaway from first-round draft pick Solomon Thomas, who was playing his first snap of the game and who pressured Bray into a quick throw.
Lining up at left defensive end, Thomas had another pressure later in the quarter while defensive end Aaron Lynch, a former starter playing against the Chiefs’ second-string defense, had three pressures and batted down a pass at the line of scrimmage.
Matt Barkley, who is battling with rookie C.J. Beathard to be Hoyer’s primary backup, was 10-17 for 168 yards in one and a half quarters of play and had success connecting to receiver Aldrick Robinson, who led San Francisco with two catches for 83 yards.
An eight-yard touchdown from Barkley to Robinson was wiped out by offsetting penalties, including an offensive pass interference call against receiver Aaron Burbridge. The 49ers settled for a field goal and led at halftime 9-7.
The third-string units for both squads took over in the third quarter.