All of the games on the profile Sinclair Dodds appear to have been either Fred Dodd or Reuben Dodds. I can't find any games that actually should be attributed to a Sinclair Dodds. I'm not sure where this name originated.
The 1920-22 Newcastle and NSW Country player was Fred Dodd (http://nla.gov.au/nla.news-article236313590) (sometimes misreported as Dodds). 1920 Country Week and Country squad (http://nla.gov.au/nla.news-article239624353), 1920 vs England (http://nla.gov.au/nla.news-article162646526), 1922 vs Ipswich (http://nla.gov.au/nla.news-article163674464), 1922 vs Country (http://nla.gov.au/nla.news-article245725502). Fred's details are: born 2 September 1895 in Newcastle, NSW, died 20 March 1983. Full name was Frederick John Dodd.
The 1924 Victoria player was Reuben Dodds (http://nla.gov.au/nla.news-article183725510). His details are: born 9 April 1900 in Invercargill, NZ, died 22 July 1983. Full name was Reuben Fraser Dodds.
Not sure where the name Sinclair came from but my original spreadsheets identified S Dodds as playing for Newcastle and Country in June 1920 that is because most newspapers both Sydney & Newcastle list S Dodds for the country week games & RLN also lists the Country 5/8 as S Dodds for the Metropolis v Country match.
The game on 28 Aug 1920 against England I identified as F Dodds as well as the 1922 games so I'm happy all these are Fred Dodd as there is no consistency in any of the newspapers some say F some say S.
No problem with Reuben Dodds in the Victorian team in 1924 again lots of inconstancy with the name in the newspapers some have S some F but also found one referring to R.F.Dodds.
I've made these changes and update all the details.