SANTA CLARA, Calif. -- As one of the few remaining stalwarts from the San Francisco 49ers' most recent run of success, left tackle Joe Staley has found himself struggling to enjoy his job in recent seasons.

On the heels of a three-year run of NFC Championship Game appearances, the Niners have won just 15 games over the past three seasons. They bottomed out last season at 2-14 and made sweeping changes to the front office and coaching staff. All of the losing wore on Staley, who is still pursuing his first Super Bowl championship as he enters his 11th NFL season.

Now, as the Niners break for the summer before returning for training camp, Staley is feeling revitalized. The biggest reason? New coach Kyle Shanahan.

"I haven’t felt like this in a long time," Staley said. "This might sound kind of bad but I’m enjoying football again. Excited to come to work every single day. The last couple years there were days where I couldn’t honestly say that. So that’s awesome to have that feeling back. I’m really, really excited about the new staff. Kyle is by far one of the most intelligent coaches that I’ve worked with."

It's important to note that for any new regime, there's always a built-in honeymoon period. For many teams making changes, those alterations came as the result of losing. Big changes often represent hope for fans and players alike. For anyone who wants to compare the praise the Niners are heaping on their new coach to previous changes, there's something deeper than just the chance to begin anew that's driving the compliments.

It centers on the word Staley used to describe Shanahan: intelligence. As an offensive coordinator, Shanahan earned a reputation for knowing what buttons to press to move the ball and score points. In just a few short months, Niners players are seeing that it goes much deeper than calling the right play at the right time.

They marvel at Shanahan's ability to explain the exact responsibilities of players on both sides of the ball on every play and the attention to detail that allows him to explain why every player matters on any given call.

As quarterback Brian Hoyer puts it, Shanahan's emphasis is more on the whys and less on the whats.

"One of the coolest things, I thought, is when we have our team meetings Kyle puts up plays and he explains them both from an offensive perspective and a defensive perspective," Hoyer said. "So, I sit next to [linebacker] Dekoda Watson and he's like, 'Man, I never even knew half of this stuff, like who has got a certain gap and how we're trying to affect that gap.' I think that's one of the great things about Kyle as a coach, is that he is able to break it down to the simplest level, whereas I think a lot of times in this league that people bypass that and they just want to tell you, 'Just do this.' Kyle is always good about giving you the 'why.' 'This is why we're trying to do this. This is why we're trying to affect this player.' And, if you're really paying attention, you'll learn a lot about football and realize what he's trying to do with his scheme.”

Of course, explaining how things should work can go only so far if results don't follow. During a recent practice, Hoyer finally connected on a pair of deep throws to receiver Marquise Goodwin and tight end George Kittle. Those plays came after practices in which the offense often found itself searching for traction and rarely connecting on deep balls.

"A lot of times in this league ... they just want to tell you, 'Just do this.' Kyle is always good about giving you the 'why,'" one 49ers player said of new coach Kyle Shanahan. AP Photo/Jeff Chiu

They also came as the result of play-action passes, a staple in the Shanahan offense. Instead of simply rolling with the success of those plays, Shanahan took the time to point out to his players on both sides of the ball the keys to make it work.

For the offense, much of that weight falls on the offensive line, upon whom it's incumbent to sell the run as long as possible before retreating to a pass-blocking set. For the defense, it's about trying to instantaneously read the movements of those linemen in search of a tell as to whether it's a run or pass.

Regardless, every playcall comes as part of a bigger plan rather than just randomly pulling ideas from a sheet.

"I think methodical is the word I would use," safety Eric Reid said. "We come in here every day and have a team meeting and Coach Shanahan dissects the play. Let’s just say for a play we made a tackle for a 2-yard loss, he’ll say, 'Yeah, you may have got us for a 2-yard loss, but at the end of the day, I know if I can get you all to keep biting on this play, keep running it, keep getting you all to bite, now I can open up the play-action and we can get all those yards that you all took away plus some.'"

During a Wednesday-morning film session, Staley was sitting next to center Daniel Kilgore when Shanahan started breaking it down. For longtime veterans like Staley and Kilgore, such meetings might be seen as monotonous. Shanahan proceeded to explain in detail what the offense and defense were trying to accomplish conceptually, whom the offense was trying to attack and whom the defense was trying to force to make the play.

Even with as many snaps as they've taken, Staley and Kilgore find themselves learning things they didn't know they didn't know.

"I just kind of looked over to Kilgore and was like, ‘This is awesome,'" Staley said. "You kind of get like chills almost because it’s just cool to see football talked about that way instead of just, ‘Hey, you’ve got to do your job.’ It’s like, ‘OK, yes sir.’ It’s more like, ‘Why do I have to do my job?’ and it’s, 'Well, this is why, because I’m the reason why this play is successful or not, or the slot receiver is the reason why the running play to the right takes off.' He’s really done a good job of explaining that."

To be sure, the ultimate test of Shanahan's ability as a head coach will come when the games begin. At least for now, his football knowledge is helping him ensure his players will do whatever he asks in hopes that football will be fun again on fall Sundays and not just on a Wednesday in June.