Rinker, a member of the big tour from 1995-99, is playing his second consecutive season on the Buy.Com Tour. Last year, he made 18 of 27 cuts, but failed to crack the top 30 on the money list.
This year, things have been worse.
The 40-year-old is 82nd in earnings - one spot better than big brother Larry, who is conditionally exempt on the PGA Tour.
The younger Rinker has missed seven of 11 cuts in 2001 and had only four sub-70 rounds under his belt entering this weeks Buy.Com Dayton Open.
However, Thursday at Yankee Trace, Rinker fired an 8-under-par 64 to earn a share of the first-round lead in Centerville, Ohio.
Rinker is tied with Todd Barranger for the top spot as Thursday's play was cancelled due to rain.
Barranger is coming off his best finish of the season, a tie for sixth at the Greater Cleveland Open. He started the first round with an eagle at the par-5 1st and recorded three more birdies to make the turn in 5-under 31.
Barranger played the back nine in even par over the first 14 holes before birdieing the 15th, 17th and 18th holes.
Likewise, Rinkers round consisted of one eagle, seven birdies and a bogey.
Play was suspended at 4:50 p.m. and officially called for the day at 6:00 p.m.
Richard Zokol and Rick Cramer are both just one off the lead after a pair of 7-under-par 65s. Zokol is making his first start since winning the Canadian PGA Championship two weeks ago.
Seventy-eight players failed to finish their first rounds.
Full-field scores from the Buy.Com Dayton Open