Pádraig Harrington speaks to reporters after his opening 66

Pádraig Harrington's short game and putting save him as he returned from his freak elbow injury with a four-under 66 in the Travelers Championship at TPC River Highlands.

But Rory McIlroy revealed that the new TaylorMade Red Spider putter he put in the bag for the US Open had been put on notice after he missed five putts inside 10 feet and was forced to settle for a three-under 67.

As Jordan Spieth finally saw some form on the greens this year, making eight birdies in a seven-under 63 for a one-stroke lead over Johnson Wagner and Brett Stegmaier, McIlroy was less that happy with a three-under-par effort that required 30 putts.

"I come off the golf course a little disappointed with a 67 because I gave myself so many chances," McIlroy said after making four birdies with his lone bogey a three-putt from 10 feet on his ninth hole at a course that is 1,000 shorter than Erin Hills

"Tee to green game is where it needs to be... It's just a matter of converting the chances I'm giving myself.

"I shot three-under today, but it could have been a whole lot better. So I'm looking forward to getting after it again tomorrow and over the weekend.

"I hit some good putts. I think I hit the hole five or six times. A few of those go in, it's a different story, and all of a sudden you're shooting something in the low 60s and you're feeling really good about yourself.

"Just have to stay patient and keep trying to hit good putts, and hopefully they will drop."

Searching for momentum after playing just seven events this year, McIlroy is hoping a run of six events in eight weeks will give him the game time to get back to where he believes he belongs.

But he is also prepared to be patient and wait for his game to "catch fire."

"You can't force it," he said. "I've tried to force it in the past, and it doesn't work. You never know when your game is going to catch fire.

"You work away, work on the stuff you need to, and sometimes it happens earlier than you think, and sometimes it happens a little later.

"Even last year, I caught fire at the end of the season and won a couple of events in the playoffs and all of a sudden won the FedEx Cup.

"It's just about staying patient and knowing that if you are doing the right things off the golf course, hopefully, it will all come together sooner rather than later."

His patience level may depend on how his putter behaves for the next few days.

"I made a decision this week, I'd give it one more week and see how it performed," McIlroy said. "But it's nothing to do with the putter, it's mostly what I'm doing with it."

Harrington is also looking forward to getting a run of golf after a stop-start season that began four missed cuts out of five before he bit the bullet and had surgery to carry out a disc replacement that allow decompression of a trapped nerve between the C6 and C7 joints.

It meant 12 weeks on the sidelines and after returning for the BMW PGA, US Open qualifying and the Memorial, he was then forced to take another 10 days off to recover from a fluke injury he sustained when an amateur hit him on the left elbow during a sponsor's day and inflicted a wound that required six stitches.

"That's twice this year," said Harrington, who has missed five of seven cuts this year. "I'm hoping it doesn't come in threes."

Harrington made four birdies but admitted that after scrambling eight times out of eight for par, he's struggling for sharpness due to lack of tournament play.

"I haven't played," Harrington said. "I've played 21 games of golf this year, and I am not trusting my lines at times off the tee and not picking the right shot or trusting the right shot.

"As I play a bit more, I am getting to trust it and hopefully the short game stays as strong.

"I had 13 straight one-putts to start in the Pro-Am, so I am happy I followed up today. It doesn't normally work out like that."

Set to play the Irish Open and the Scottish Open before The Open, he said: "It's been a bit of a struggle just getting momentum. … There's no substitute for being on the golf course.

"While it hasn't been a great year. I'll be happy if I'm ready for the Open."