SANTA CLARA – General manager John Lynch admitted the one concern he had about cornerback Ahkello Witherspoon as he evaluated him before the draft was his willingness to be physical.

Witherspoon was involved in the biggest hit of training camp through five practices. However, he was on the wrong end of the collision.

The 49ers do not perform any live tackling in practices. Although there is padded, contact work, the defensive players are instructed to “thud” and release -- instead of tackling to the ground.

Apparently, the same rules do not allow for players on offense.

Running back Carlos Hyde leveled the boom on a flat-footed Witherspoon at the goal line at the end of a 6-yard touchdown run.

“I’m not worried about that last play,” 49ers defensive coordinator Robert Saleh said. “They’re not tackling drills, and that caught him off guard. We’ll see when we’re actually allowed to tackle and I have full faith that Ahkello’s going to do exactly what he’s been coached to do.

“He’s not a coward by any means. He will get in there. He will tackle. He’s been showing up in run fits. He’s physical with his hands at the line of scrimmage. So we’re excited to see what shows up on game day.”

Witherspoon had a solid day in coverage, as he attempts to insert himself into the competition at cornerback. But while Keith Reaser missed his second day of practice with a knee injury, Dontae Johnson has taken the biggest strides toward securing the starting job opposite of Rashard Robinson.

Johnson had his best day of camp, including a leaping interception of a Brian Hoyer pass intended for Jeremy Kerley. It was Hoyer’s first interception during 11-on-11 drills since the opening of training camp. Johnson also got physical to break up pass for a Aaron Burbridge in the end zone during 7-on-7 drills.

The 49ers want to see a style of play such as what Johnson demonstrated on Wednesday. When the games begin, the best way for Witherspoon to rise up the depth chart will be to feature a more physical style and deliver the hits instead of being on the receiving side.

QUICK SLANTS

--Defensive lineman DeForest Buckner sustained a left ankle injury midway through practice. Although he initially appeared to be in significant pain, he ended up watching the remainder of practice from the sideline.

--Safety Eric Reid (ankle) and tight end George Kittle (hamstring) participated in individual drills. Safety Jaquiski Tartt (ribs), linebacker Eli Harold (head), cornerback Keith Reaser (knee) did not practice and are listed as day to day.

--Defensive back Adrian Colbert recorded an interception of a Matt Barkley pass after a miscommunication with his receiver placed no offensive player anywhere near Colbert in the middle of the field.

--Ahmad Brooks recorded two sacks and broke up a Hoyer pass over the middle that was inteded for tight end Garrett Celek.

--Barkley hooked up with undrafted rookie tight end Cole Hikutini over safety Lorenzo Jerome for a deep pass play down the seam.

--Rookie Trent Taylor made an exceptional catch during a 7-on-7 drill, making a leaping catch of a Barkley pass, then, somehow managing to get both feet inbounds at the pylon at the left front corner of the end zone.