I wasn't really having much high expectations as opposed to just getting out there and playing my golf.
But it was an unhappy first round for Australia's Jason Day, who succumbed to a back injury and withdrew after completing only six holes.
Mickelson's double-bogey came at the expense of one of the more daring shots of the day as the five-time major victor attempted a right-handed effort behind a net. "Obviously, playing at Bay Hill with him I know how special this event is for all of us, I can only imagine how special it is for him".
Elsewhere Thursday, reigning Masters champion Patrick Reed was five shots off the lead in 15th place after a two-under-par 70.
"I wouldn't say I'm thrilled with two under, but it was pretty good considering; I probably got the best score out of my performance", Leishman told AAP.
Strong storm system brings the rain
Precipitation will wrap up around noontime Sunday on a cloudy day in which the high temperature will be in the low 40s. There could be large waves for coastal areas, bus and train services affected and delays for high-sided vehicles.
"Whether it was Mexico, Riviera or Torrey Pines, I left happy with where my game was even though I didn't win", McIlroy said. He was helped by a pair of 30-foot birdie putts near the end of his round and a 10-foot par save at No. 9 on his final hole.
Second-ranked Justin Rose of England is tied for 33rd at 71, defending champion and sixth-ranked Rory McIlroy of Northern Ireland totaled 72 and is tied for 49th, seventh-ranked Rickie Fowler of Murrieta finished at 74 and is in a tie for 72nd that includes third-ranked Brooks Koepka, and fifth-ranked Bryson DeChambeau is tied for 85th at 75. "It's a penalizing course if you don't hit very good shots, and I hit some awful shots today".
World number 34 Cabrera Bello, a three-times victor on the European Tour, is seeking his first victory on the PGA Tour.
Everything was picture ideal during Round 1 of the Arnold Palmer Invitational at Bay Hill on Thursday. This could be a big week for him in other ways.
The Mount Juliet golfer eagled the 18th to race to the turn in four-under 32 and move into the top-10 on five-under.
Teen Tells US Senate Why He Defied Anti-Vaccine Mother
They in turn are a hazard to people who can't get vaccinated - babies who are too young or people with weak immune systems. Measles is highly contagious and can live in a room for two hours after an infected person coughed or sneezed.
"It is just a matter of doing the right things and doing them day after day and if I do all those maybe tomorrow is the day".
"I only found that out on Tuesday, to be honest with you", McDowell said.
"It just wasn't going to work out".
"I (aggravated) it last Sunday", he said, "and then got an MRI Monday, which came back that I had an annular tear in my disc, and then I've got set problems as well".
Conflicting reports of Bills-Steelers trade for Antonio Brown
Brown took issue with something and didn't play in Week 17 against the Bengals despite the Steelers still in playoff contention. Rapoport then tweeted that the deal isn't official, but doubled-down that it's on it's way to happening.