Melbourne's reigning champion jockey Luke Nolen returns from his off-season break to begin the pursuit of runaway premiership leader Glen Boss at Sandown on Wednesday.

But at best he will only be able to reduce Boss's 15-win lead by one.

Nolen's only ride for the day is Aliberani who isn't without a chance in the Le Pine Funerals Handicap (1800m).

Nolen's skinny book compares poorly with Boss's five rides on the seven-race card, a couple of which have strong winning prospects.

Boss opens with Portfolio in the KS Environmental Handicap (3000m), a South Australian stayer with respectable form in an ordinary race.

He rides the unraced Stratum filly Sworn Revenge who is equal on form to all but one of her opponents in the Swettenham Stud Dash For Cash (900m) and Chelembra appears to have moderate prospects in the Dunlite Handicap (1000m).

Then comes Boss's best two hopes for the program, Silver Trinket in the Sportingbet Handicap (1600m) and Onpicalo who resumes in the Swettenham Stud Summer Championship (1300m).

Silver Trinket broke through last start after six moderate efforts and although she is up against the obvious favourite Hazard, she has a handy pull in the weights.

Onpicalo, a winner at her first two starts when ridden by Boss is his best for the day, his main opposition looking to be stablemate General Offer who has won his past two on country tracks.

As well as being on top of the Melbourne jockeys' premiership, Boss is the leading money-winning rider in Australia this season, his mounts having collected almost $7 million.

His closest rival on the prize money list is Craig Williams who is in 125th place on the national jockey's table with 24 winners who have collected $5.3 million.

On top of the winners' list is Victorian Brad Rawiller who has had 85 victories for the year on all tracks, almost twice as many as his brother Nash.

Rawiller has also had more rides than any other jockey in Australia this season, his 472 mounts up to the start of this week coming at an exhausting average of around 85 a month for the season so far.