ARLINGTON HEIGHTS, Ill. – Maristar went off as the surprisingly solid favorite June 25 in the $103,000 Trillium Stakes at Woodbine, and she probably will be the chalk again if Saturday’s featured race 6 is rained onto Arlington’s main track.The featured sixth is carded for 1 1/8 miles on turf, but after getting pummeled by heavy rain late last week, the Chicago area was hit with another round of precipitation Wednesday night and Thursday morning, and with Arlington sure to treat the grass course cautiously with Million Day approaching, Saturday’s races easily could wind up on Polytrack.That would make way for Maristar, who was entered only for the main track by trainer Gerard Butler. Butler has Akhmatova among seven horses in the main body of a high-end allowance race also open to $80,000 claimers, but Maristar is the one to watch. One of Butler’s two winners at the Arlington meet, Maristar, a 4-year-old filly, shined in a May 21 race at this class level and distance, beating a solid field of males with a nice stretch run. Still, it was surprising to see her favored over the likes of Upperline in the Trillium, and while Upperline delivered a representative effort to win this race, Maristar appeared to bounce badly off her U.S.-debut victory, fading to a distant last of five after tracking a slow pace. Maristar, however, has come back with two lively recent Arlington works, suggesting she may be coming back around to the form she showed here in June. Mike Stidham trains Upperline, and in Saturday’s race he sends out Ruthville, who could contend on either turf or synthetic. Ruthville went evenly finishing a close fourth behind the good filly Embur’s Song last out in the Windward Stakes at Presque Isle, and earlier this meet won allowance races on both the main and turf tracks.Pathway exits a second-place finish in the Lincoln Heritage Stakes for Illinois-bred turf fillies, a performance that puts her squarely in the mix Saturday. Pathway, however, is less accomplished on Polytrack and may need the race to remain on turf for her best chance. Sweetbriar Academy is doubled in claiming price, from $40,000 to $80,000, after winning two straight races for the surging Wayne Catalano barn. She is not overmatched in a quest for three in a row, but is another horse who probably needs grass to produce her best showing.