The test for Jimmy Garoppolo as he enters his first full campaign as a starting quarterback will be adjusting to defenses that spent their offseasons adjusting to him.

It’s why playing quarterback in the NFL is so hard. Once you play well, opposing coaches and players use the time between February and August to dissect your flaws.

That’s why year-to-year consistency is what separates the great quarterbacks from the rest. It’s also why some are skeptical of Garoppolo given his small seven-game sample as a starter during his four seasons.

“That’s the NFL for you in a nutshell,” Garoppolo said. “Everybody has tape on everybody. You’re studying for an entire week. You go years and years back on some guys and some D-coordinators or some quarterbacks. That’s the game we play. … It’s about who does it better at the end of the day.”

Garoppolo was one of the league’s best quarterbacks during his undefeated five-game stint to end 2017. The 49ers had the league’s third-ranked passing attack (297 yards per game) and total offense (410 yards) during that span, even while Garoppolo was working with a mostly unestablished supporting cast after just four weeks to learn Kyle Shanahan’s complex offense.

But new cornerback Richard Sherman has already identified a small flaw in Garoppolo’s game. It’s a tell that might allow defensive backs to get a jump on his throws.

“When he takes his hand off the ball, you got to be ready to break,” Sherman said after watching Garoppolo closely throughout the offseason program.

In other words, Garoppolo doesn’t mix up the timing of his deliveries. He secures the ball in the pocket with two hands, but when his left hand starts to come off, he’s throwing.

Some quarterbacks vary their deliveries by patting the ball with their off hand. It can disrupt the timing of defensive backs who have their eyes in the backfield.

“If he takes his hand of the ball, and doesn’t throw it, I think he’ll throw guys off,” said Sherman, who noted Garoppolo had one of the league’s quickest releases, though it’s a notch below Packers star Aaron Rodgers.

Garoppolo’s tendency is a minor flaw, to be sure. But a split second can be the difference between a completed pass and an interception. Perhaps adding pump fakes and other nuances will be in the next evolution of Garoppolo’s game. He threw an interception in all five starts last season after not throwing any in 94 career attempts before joining San Francisco.

“Yeah, the defense has told me that,” Garoppolo said of Sherman’s observation. “But at the same time, I use that against them because they’re thinking that. It’s a game of cat-and-mouse. It always is. They’re reading you, you’re reading them at the same time. It’s a ‘who flinches first’ type of thing. We’ve had some good battles and it’s been a good camp.”

Sherman and Garoppolo, the team’s two most notable players, didn’t go against one another during the offseason program, their first since joining San Francisco. That could change at the start of training camp in late July when Sherman is expected to be cleared by team doctors.

Sherman spent the spring recovering from surgeries on both Achilles tendons. He participated in the team’s recent two-day minicamp but was limited to individual drills, leaving proteges Tyvis Powell and Ahkello Witherspoon to start in his place during 11-on-11 drills. That duo played well against Garoppolo and the offense sputtered more noticeably than other practices open to reporters.

Sherman said when he signed with the 49ers that Garoppolo was part of the of the appeal. San Francisco is widely considered a bounce-back candidate to get to the playoffs for the first time since the 2013 season.

“You can see a lot of the things that he learned from Tom (Brady),” Sherman said of his new quarterback.