By Michael Donovan

If you are wondering whether third-year Eagles tight end Zach Ertz can make the next leap into the NFL’s elite, know this:

He mapped out his most intense offseason regimen and he’s been reaping the benefits from the moment training camp opened on Sunday as a standout in each of the first four practices.

“I’m never going to be satisfied,” he said after Thursday’s practice at the NovaCare Complex. “There’s areas to improve in my receiving game, in my releases, in my hands, the blocking as well. Where I am now in every facet of the game is not where I want to be. I want to be one of the best, and that’s what I’m going to work toward.

“I attacked [the offseason] to improve the blocking aspect because I want to be on the field every play.”

Which has been his only real obstacle toward becoming a high-volume receiver.

As a rookie in 2013, Ertz caught 36 passes for 469 yards and four touchdowns while playing just 41 percent of the offensive snaps. The two main reasons for the 41 percent? Starter Brent Celek and Ertz’s inability to become a top-flight blocker.

Last season, Ertz played 50 percent of the snaps and increased his catch total to 58. The two main reasons for only 50 percent? Same as above.

When Ertz was selected early in the second round of the 2013 NFL Draft, visions of two and even three tight ends on the field at the same time danced in almost everyone’s heads. That wasn’t hard to understand because head coach Chip Kelly, who also was an NFL rookie that year, came in with a run-first mentality, the anti-Andy Reid.

But it hasn’t turned out that way, even though Kelly kept four tight ends on the roster last season and even though Celek’s receiving numbers have dropped to dangerously low levels.

The 30-year-old last season was limited to 32 catches for 340 yards, one TD and an average of 10.6 yards per reception. Each of those statistics represented career lows since he became a full-time starter in 2009. Yet he played 69 percent of the snaps and remains a teacher’s pet of Kelly, who has most recently allowed Jeremy Maclin (career highs of 85 catches, 1,318 yards and 10 TDs) to leave in free agency and jettisoned DeSean Jackson for no compensation following an 82-catch, 1,332-yard season in 2013.

To crack Kelly’s elusive A list, Ertz has done everything in his power during an offseason that began with, well, increasing his power.

In the six weeks between minicamp and the opening of training camp, Ertz went to California to train with some teammates under Todd Durkin and retired offensive line coach Hudson Houck in San Diego.

Ertz mixed strength training with endurance drills, mixed martial arts and boxing in an effort to return to Philly as the complete player he always believed he could become.

“I was blocking a lot, working with a Hall of Fame offensive line coach, working on some boxing stuff, working on my hands,” Ertz said. “It was a very thought-out process, and I think I executed it well.”

Kelly has noticed a difference and appreciates it.

“His footwork and hand placement and things like that have really improved,” Kelly said. “But now when you get to days like this, hopefully we’ll be able to take the next step with him. But I really think he’s worked extremely hard at it. What we could get accomplished from a blocking standpoint, with just helmets on in the offseason program and in the last two days, I think he’s done a real good job.”

Enough to become a regular in the offense?

That will be determined over these next few critical weeks.

Ertz has a feeling 2015 will be memorable from that standpoint.

“In the first [training camp] I was swimming in the playbook, swimming with the adjustment period because I didn’t have the OTAs or anything,” he said. “Last [year], I was more comfortable but didn’t really understand techniques and how to use them to my advantage.

“Now I feel like I’m a veteran. I know what I’m supposed to do and how I’m supposed to get the job done. Now it’s just a matter of fact of get