"All of the things we saw on tape are translating here," said general manager Howie Roseman after yesterday morning's workout. "It's a big step, but he's doing a great job."
"He's got a pretty high skill set," said offensive coordinator Marty Mornhinweg. "He's really got a chance to possibly help us, early."
It helps that, already, Harbor has the endorsement of the most important man on the team; that is, the guy who will be throwing him the ball.
"I'm super impressed with the way he's performed this week," said quarterback Kevin Kolb. "He's got plenty of talent. Plenty of instincts. But my biggest impression with Clay is he gets better every single day. You tell him something, he fixes it the next day. That's what you want to see from a young guy."
And, yes, there are things to fix. Given his pedigree, there should be.
Harbor was an unrecruited, 185-pound wide receiver in high school whose brother, Cory, convinced the football coaches at Missouri State to give him a shot. Clay then redshirted before converting to tight end - a conversion that took place just before his first collegiate game, when the top two tight ends went down with injuries.
Harbor, who had gained 15 pounds during his redshirt year, played tight end off and on that season but converted to tight end full time when he gained another 10 pounds before his second season of playing.
Projected to be undrafted after his senior season, it took a strong postseason effort at the combine and at two All-Star games to make Harbor a middle-rounds projection.
His rawness shows.
He didn't get his head around quickly enough in 11-on-11 drills yesterday and a pass to him was defended.
"Sometimes, when you're trying to get things right mentally, you're a little behind on the other things," Kolb explained.
Also, in college, at 6-3 and 252 pounds as a senior, Harbor didn't need to perfect blocking techniques to be effective – the area in which he needs the most work.
"Sometimes I'll take a bad step, or I won't step at all. Sometimes my hands will come outside, and I need to fire them inside," Harbor said. "That's huge, at this level. If you don't use the right footwork and put your hands in the right spot, you don't even have a chance to win. You're not going to out-athlete or out-power anybody here, in the NFL."
It is one of many adjustments Harbor quickly has made – adjustments he wanted to show weren't all that hard.
"Coming from a smaller school, you just want to show people you belong," he said, and refute the perception that, maybe, "you can't adapt to the high level of competition."
Certainly, a fourth-round pick drafted for his good hands – Harbor caught 150 passes for 1,906 yards and 10 touchdowns in school – shouldn't need too much time to adapt.
After all, training-camp standouts like Greg Lewis, Chad Lewis and Hank Baskett went undrafted.
Jason Avant, like Harbor, was a fourth-round pick, but, then, Avant went to school at Michigan, where things are much higher profile than at the place formerly known as Southwest Missouri State (which also produced Phillies slugger Ryan Howard).
Starting tight end Brent Celek, a fifth-round pick in 2007 and a product of football outlier Cincinnati, advised Harbor last week that where he came from mattered less than knowing where he is going. It is what Celek learned as a rookie standout himself.
"When I first came to mini-camp, my head was kind of spinning," Harbor said. "I thought, 'Wow, these guys are fast – a lot different from Missouri State.' "
Then, upon the beginning of training camp, Celek slowed down Harbor's football world: Run the route, make the block, do it quickly, and everything else will come.
Said Harbor, "Brent told me, 'The speed of the game gets faster. But if you do what you're supposed to do, what you've been coached to do, it doesn't even matter, if you're at the spot you're supposed to be at.' "
So far, that advice has served Harbor well. So has fate. There are four tight ends at camp.
Second-year tight end Martin Rucker injured his hamstring at yesterday's practice.
Second-year tight end Cornelius Ingram, a fifth-round pick out of Florida in 2009, is coming off a second knee surgery in as many years.
"We understand he's coming off a double-knee surgery and he hasn't played in quite some time. He's right in the middle of that learning curve," Mornhinweg said. "He's got terrific athleticism. We expect excellent things out of him – just when, is the key."
So, they need excellent things from Harbor, and soon.
Roseman spoke highly of Harbor's ability to learn and his love of playing, attributes underscored by Harbor's professed eagerness to play special teams.
"I want to be on a lot of special teams. I like to run, and I like to hit people," Harbor said.
Playing special teams might make Harbor more valuable and versatile, but it isn't likely to make the same sort of impression as his hands have made – especially with Kolb. That's important, since Kolb loves to use the tight end; in his two starts last season, he hit Celek 11 times in the first game and eight in the secondfor 104 yards in each game.
"On this team, we have the speed. We have the big guys. We need somebody inside who thinks and feels like a quarterback," Kolb said. "Obviously, Brent Celek's one of those, but we'll take two of them. And two tight ends is very important in this offense. We have to have that set."
Whether Harbor can get on the field and make that set a weapon will be determined less by what happens at Lehigh and more by what happens during the last three Friday nights in August, when the Birds play their preseason games. Can he adjust to the speed, the hitting, the verbiage?
"We're really eager to see him during the games and see more of what he's got," Roseman said.
They're really happy with what they've seen so far.