Ana Pelaez Trivino, a winner on the Ladies European Tour competing as a rookie on the LPGA circuit this year, was playing in her third AIG Women’s Open this week, and playing well. Rounds of 72 and 74 in tricky conditions over the opening two days on the Old Course at St. Andrews put her at two over, 10 strokes back of halfway leader Nelly Korda but comfortably inside the cut line for the first time in her career in a major.

But Pelaez Trivino won’t be back for the weekend after the R&A announced on Friday that the 26-year-old Spaniard had been disqualified because of a rules violation. According to the R&A, Trivino’s caddie, Miguel Evangelio Gomez-Escolar, used a distance measuring device on the 10th and 18th holes during Friday’s second round. The R&A, however, prohibits the use of DMDs for the championship under Model Local Rule GS.

Had Gomez-Escolar only used the device once, Pelaez Trivino would have been assessed a two-shot penalty and been able to make the cut at the Old Course right on the number. But because he used it a second time, the penalty applied under Rule 4.3 was a disqualification.

A possible reason for the confusion is the fact that players can use distance measuring devices during LPGA Tour events, and they also are allowed at the Chevron Championship, KPMG Women’s PGA and the Amundi Evian Championship. The only two majors that prohibit their use are the U.S. Women’s Open and the AIG Women’s Open.

“It’s not anyone’s fault,” Pelaez Trivino said in Spanish on her Instagram account Friday afternoon. “If anything, it’s my responsibilty. I was disqualified because [my caddie] was using a laser in a tournament that you were not allowed to. I was trusting my caddie, and I didn’t read the little paper, which was my responsibility. And he assumed you could use a laser like in every other tournament and didn’t read the little paper either.”

The mistake could prove costly for Pelaez Trivino, who has made just three cuts in 10 LPGA starts this season, her best showing coming last week with a T-48 finish at the ISPS Handa Women’s Scottish Open. Entering the Women’s Open, she ranked 170th in the season-long Race to the CME Globe points standings, with the top 100 at the end of the year keeping their cards for 2025.