Abraham Ancer … Let's try this again. After securing an exemption into last year's edition as Mexico's highest-ranked golfer, he's risen about 200 spots in the Official World Golf Ranking. Although he still needed the same exemption for the opportunity to improve on last year's T52, the U.S.-born dual citizen has gone off for seven top 10s since his debut at Club de Golf Chapultepec, including a victory at the Emirates Australian Open three months ago. Currently inside the top 10 on the PGA TOUR in Strokes Gained: Off-the-tee, total driving, proximity to the hole and scrambling. If he breaks through, it'd be cause for a national celebration, but it'd also be a dandy birthday present. He turns 28 on the Wednesday following the tournament.
Russell Knox … He's back to doing Russell Knox things with three top 20s in his last four starts. That surge includes a T14 in his last appearance at the AT&T Pebble Beach Pro-Am where he ranked T16 in greens in regulation and led the field in scrambling. For the season, he's sixth on the PGA TOUR in proximity to the hole. Debuted at the Club de Golf Chapultepec in 2017 and settled for 70th place during what already was setting up as a slump.
Byeong Hun An … Although based on the PGA TOUR on which he took advantage of starts in all three events on the Asian Swing in the fall, he's added several starts on multiple tours before and since. Yet, the 27-year-old hasn't let up, striking with five top 20s in eight starts over the last five months, including in his last two. Builds confidence with his power and precision, but he also stands over putts with a scorer's mentality, so it's just a matter of time before he's celebrating his first TOUR victory. Returns to Mexico City since finished T48 in 2017 when he ranked T10 in total driving and fourth in proximity to the hole for the week.
Richard Sterne … The veteran of 59 PGA TOUR starts and one membership card (2014-15) hasn't connected for a top 25 on the circuit in 29 starts spanning five years. However, he's opened 2019 strong with a runner-up finish in Abu Dhabi and a T13 in Saudi Arabia. Currently fifth on the European Tour in par-3 scoring and 17th in par-5 scoring. The 37-year-old from South Africa also isn't inexperienced at Club de Golf Chapultepec where he appeared in 2017 (T72).
Adrian Otaegui … The only first-timer at Club de Golf Chapultepec on this page is fresh off a runner-up finish at the ISPS Handa World Super 6 Perth, so the impact of fatigue and jet lag cannot be ruled out for the spry Spaniard even at 26 years of age. That result in Australia vaulted him to 64th in the Official World Golf Ranking and into this week's tournament as the last man in the field, ironically leaving Super 6 champion Ryan Fox as the first man on the outside looking in. Otaegui finished 23rd in the 2018 Race to Dubai with the help of a victory last May. More recently, he's recorded five top 25s in his last nine starts worldwide.
NOTE: Sleeper is a relative term, so Rob uses unofficial criteria to determine who qualifies. Each of the following usually is determined to be ineligible for this weekly staple: Winners of the tournament on the current host course; winners in the same season; recent major champions; top 50 in the Official World Golf Ranking; recent participants of team competitions.