Last year, with Peters on the shelf, McCoy's numbers in those three categories plummeted to 4.2, 70.0 and 2.
"You can't replace somebody like Jason," the Eagles' former offensive-line coach, Howard Mudd, said late last season. "You just try to minimize the damage."
Peters' two replacements at left tackle last season - King Dunlap (11 starts) and Demetress Bell (five) - ended up being the equivalent of a Band-Aid on a gunshot wound.
McCoy's rushing average on runs to the left side nose-dived from 5.0 yards per carry the year before to 3.2 sans Peters.
In '11, Peters allowed just three quarterback sacks, one hit and 17 hurries in 954 snaps, according to Pro Football Focus. Last year, in a combined 1,159 snaps at left tackle, Dunlap and Bell gave up seven sacks, 12 hits and 34 hurries.
"Seeing my teammates go out there and battle and not being out there with them, that was the hardest thing for me," Peters said Tuesday.
"I was in the meetings watching film with them and showing them the corrections and stuff. But any time your team is struggling, especially that group of guys on the offensive line, it's hard."
You can argue that one player wouldn't have made much of a difference in last year's 4-12 disaster. But Peters begs to differ.
"[I would've made] a big difference," he said. "I'm a starter. I'm the No. 1 offensive lineman in the league. Me being out there carries everybody else [to a higher level] and makes them play their best."
Peters was at the NovaCare Complex Tuesday participating in the Eagles' voluntary offseason strength and conditioning program, which got under way this week. He said he has made a complete recovery from the two Achilles' tears and is determined to pick up where he left off before the injury.
"I'm just working to get back to where I was before I got hurt," he said. "I want to get back to where I used to be and get some [playoff] wins. I've never had one. I don't know what it feels like. I can't wait to feel it."
It remains to be seen whether the Eagles and their new coach, Chip Kelly, can rise from the ashes of last season's 12-loss debacle and make a playoff run in 2013.
They've made an earnest attempt to improve their defense this offseason. Seven of their nine free-agent signings have been defensive players.
We still don't know who the quarterback is going to be. But, the offensive line in front of Mr. X should be much improved with the return of Peters, center Jason Kelce (MCL and ACL tears in right knee, missed 14 games) and right tackle Todd Herremans (broken right foot, missed eight games).
Peters and Herremans both have been cleared to do everything. Kelce may be limited in the team's predraft minicamp, but should be ready to go when OTAs commence in May.
"I'm excited," Peters said. "Me and Todd both are excited. We talked about it [Monday] in the [team] meeting. We're excited to get back out there."
Said Herremans: "It seems like it's been forever since we all played together. It'll be interesting to see what we do in the draft or free agency, whether we try to shore up the other spot [right guard] a little bit, or where I'm going to be playing."
The Eagles remain interested in free-agent tackle Eric Winston, according to sources, which would seem to indicate they are open to the idea of moving Herremans back inside.
It's also possible they will use their first-round pick - the fourth overall - on an offensive lineman, which would make sense, since Peters turned 31 in January and Herremans is 30. Hardly ready for the boneyard, but old enough that you've got to start thinking about the future, particularly with both of them coming off major injuries.
Asked Tuesday what his reaction would be if the Eagles drafted a potential left-tackle replacement like Texas A & M's Luke Joeckel or Central Michigan's Eric Fisher, Peters said, "I hadn't heard that. But it doesn't matter who they bring in. It's not going to be easy [for somebody] to get my spot, I know that much. Whoever they draft, if they draft a left tackle, it don't matter. I'll help him work to eventually be as good as me or better."
Peters has 2 years left on his contract. His base salary this year is $10.4 million. He also has a $350,000 workout bonus. His base for 2014 is $9.65 million.
The fact that the Eagles didn't approach him about a pay cut indicates they think he can return to his 2011 form. That, and the fact that they had a lot of cap room. Peters, who spent last season on the team's reserve/non-football injury list (he initially tore his Achilles' working out on his own in Texas), said he probably could have come back and played late last season, but decided against it because the team was in a death spiral.
"I was going to come back last year, but I didn't want to risk it with a losing season," he said. "And the coaches kind of held me back a little bit."
Peters, who said he has been close to 100 percent since December, said he's been told by doctors that he's at no greater risk of re-tearing his Achilles' for a third time than someone else is of doing it for the first time.
He wants to get his weight down to 320, not so much to take stress off his Achilles', but to help him deal with the rigors of Kelly's go-go-go up-tempo offense.
"The coaches haven't said anything, but personally I want to get down [to 320]," he said. "[At that weight], I'll be ready for whatever they throw at us, whether we run 100 plays [a game] or 60."
Two days into the voluntary workouts, Peters - and the rest of the Eagles players - already are finding out that Kelly is all about speed, whether it's in the weight room or on the field.
"Forty [yard] work, hurdles, ladders, stuff like that," Peters said of the type of conditioning work he and his teammates have been doing. "Working the quick feet, the quick movement. [It's all about] the up-tempo pace."
For Peters, it's all about getting back to being the best. Which, in turn, would do wonders for the Eagles' resurrection attempt.
On Twitter: @Pdomo