The world No.31 only pitched up in St Louis on Wednesday after spending the start of the week at his Florida home.
But after playing only nine practice holes, Poulter shot a 67 to trail his playing partner and clubhouse leader Rickie Fowler by only two shots.
The hero of Medinah is currently 10th in the Ryder Cup rankings and his form this season has a strong case to get a wildcard from captain Thomas Bjorn.
Poulter has one more event after the US PGA to force his way into the top eight but wants to get the job done here.
“I’m close, but I need a push,” he said. “I could have got it done last weekend at the WGC-Bridgestone Invitational. That’s why I’m a little frustrated that I didn’t get it done, but I think I can squeeze in if I play well here. If I can have a strong week in New Jersey as well and edge in, it would be fantastic.”
After his final round 74 in Akron at the end of five consecutive tournaments, Poulter headed back to his Florida base for the first time since May 20 – and stayed till Wednesday morning.
“I have never arrived the day before a Major before,” he said.
“But I saw the weather forecast and saw the storm possibilities on Tuesday, and Katie and the kids were arriving home 5:00 on Tuesday afternoon from England. So for me it made sense to go home.”
It was good to get back, have a rest, unpack, fill the fridge full of food, and a couple of nights sleep in my own bed and come up early Wednesday morning. It has worked so far.”
“I played the back nine and then I walked around the front nine and hit some chips and putts. You can see everything. You can see the bunkers, landing areas. And especially when it’s as soft as this it’s not like you need to know too much about how the ball is going to land into the greens.”
Masters runner-up Fowler took inspiration from the late Jarrod Lyle as he switched his shirt to yellow to remember the Australian – and shot a superb 65 in the sweltering heat.
Lyle passed away this week after a long battle with leukemia with many players wearing yellow cancer ribbons. The American, who is seeking an elusive first Major title, said: “I was scripted to wear some sort of dark blue shirt, so luckily I had a version of yellowish. I was lucky enough to be able to talk to him last Friday, so one thing that did help is hearing kind of from him how he felt.
“It was tough news so definitely happy that we could be here and supporting Jarrod. It’s been fun to be thinking about him while we’re out there playing and we’ll continue to do that.”
South African Louis Oosthuizen withdrew from the Championship with an undisclosed injury yesterday, announcing his decision just prior to his opening round tee time.
Oosthuizen’s place in the field was taken by American Kelly Kraft.
The PGA of America refused to comment last night on reports that hackers had targetted their computer servers earlier this week and demanded a ransom.