Fast bowler Harmison, returning to the Test arena after missing the drawn series at home to Sri Lanka with a shin injury, is set to be the senior bowler in an otherwise fledgling attack.
Star pace bowling all-rounder Andrew Flintoff (ankle) - who England hope will captain the team in Australia later this year after Michael Vaughan was ruled out with a knee injury - and fellow Ashes winning bowlers Ashley Giles (hip) and Simon Jones (knee) are all currently out of Test contention.
Meanwhile Matthew Hoggard, another of England's heroes against Australia last year, is struggling to be ready in time for Thursday with a freak hand injury sustained while warming-up during the A team match against Pakistan in Canterbury last weekend.
"It's disappointing these players won't be able to take the field but, having said that, this is a good England team that's going out there," Harmison told reporters at Lord's here Tuesday.
"We can make as many excuses as we like about injuries but it's time we put them to bed."
Last year Harmison produced a sensational spell of bowling at Lord's on the first day of the Ashes, hitting opener Justin Langer and getting a delivery through Ricky Ponting's grille to cut the Australia captain's cheek while taking five for 43 as the tourists were dismissed for 190.
But despite those figures he said he was still uncomfortable at the 'home of cricket' where the Lord's slope has disturbed many a bowler.
"It's a place I don't enjoy bowling at but I've always taken wickets here whether I've been playing for Durham or England.
"Even during the Ashes I felt a tad uncomfortable, I was still not 100 percent convinced of my rhythm. It probably is the slope."
Harmison, who returned to international action during England's 5-0 one-day series thrashing by Sri Lanka, has bowled just 32 first-class overs this season taking four wickets for 95 runs.
"I feel strong," the 27-year-old Durham player insisted. "I'm going in fit. If I didn't feel that, I would hold my hands up and say I need more time.
"But I'm ready to play," he added after a One-day series where he struggled for accuracy.
"I wasn't consistent in anything: lines, lengths, or spells. I did feel a bit rusty. But I'm not making excuses.
"Hopefully, the Test matches will be different and I'll bowl like I can do."
Since the end of 2004, when he was ranked the world's No 1 Test bowler, Harmison's form has tailed off.
In 17 Tests for England since then he has taken 55 wickets at an expensive 37.5 apiece. And, excluding matches against minnows Bangladesh, his figures are an even more disappointing 43 wickets at 41.6 in 15 matches.
But Harmison, who in his 41 career Tests has taken 159 wickets at a shade under 30, insisted: "I don't feel I have a point to prove."
England have not won a Test series since the Ashes, losing 2-0 in Pakistan and drawing away to India before being held by Sri Lanka.
"The one thing we haven't been doing in recent times is nailing Test matches," Harmison explained. "We've got to get back to doing the basics well, scoring 400+ (in the first innings) and taking 20 wickets."
Pakistan have injury problems too with spearhead quick Shoaib Akhtar definitely out with an ankle problem and fellow pacemen Mohammad Asif and Mohammad Sami battling injuries.