Former IRL IndyCar drivers Scott Harrington and Billy Roe have joined the field for the historic Freedom 100 Infiniti Pro Series event at Indianapolis this weekend, swelling the field to a series-best 19.

Harrington, who returned to the IRL IndyCar Championship with Brayton Racing last year at Michigan following a much publicised battle with alcohol, has stepped into the #25 AFS Racing Dallara-Infiniti where he will team with veteran Gary Peterson.

39 year-old Harrington first came to the Indianapolis Motor Speedway as long ago as 1989, when he originally completed Rookie Orientation Practice. Despite several attempts Harrington has started but one Indy 500, the first IRL '500 in 1996 where he was classified 15th after a crash.

A semi-regular on the IRL circuit during its formative years, Harrington failed to qualify at Indy in 1997, 1998, 1999 and 2000 before leaving the racing scene later that year due to alcohol and drink/driving problems.

Clear of his problems, Harrington returned to the Indianapolis Motor Speedway last year with Brayton Racing for yet another unsuccessful qualifying attempt but finally made his return to the IRL with a decent showing in outdated equipment at Michigan.

Roe, who was part of the unfortunate Zali Racing 'experience,' which ended with his non-qualification at Indianapolis last year, has joined the Bowes Seal Fast team, which returns to the series after contesting the inaugural Championship in 2002.

The Texan born driver has amassed two career Indy 500 starts, in 1997 and 1998 but failed to finish on both occasions.