Current test batsmen Phil Hughes, Usman Khawaja and David Warner and test hopeful Ed Cowan are playing for a Cricket Australia Chairman's XI in a three-day game against India in Canberra this week.
While Watson is likely to be rushed back into the side at the expense of opener Hughes, uncertainty surrounds Watson's role.
Amid speculation the star allrounder will be moved to the middle order because of his bowling workload, Watson is no certainty to bowl in next week's Melbourne test and may play as a batsman only.
This could open the door for Christian to play the role of allrounder and bat in the top six, at the expense of either Usman Khawaja, Mike Hussey or Ricky Ponting.
Arthur expressed confidence in veterans Ponting and Hussey yesterday but added no one was guaranteed a game and they had to keep producing runs to be selected.
Arthur said he was unsure on the fitness of Watson and Marsh and this would be established overnight before the squad was announced today.
"Our preference for balance of the team is always to try to have an allrounder and if we've got one who we think is capable of doing the job, he will play," Arthur said.
Arthur said playing back-to-back tests in Melbourne (December 26-30) and Sydney (January 3-7) would be tough on a four-man bowling attack.
"I see the spinner [Nathan Lyon] bowling a huge amount more and we need to be able to fiddle some overs from our batters," Arthur said.
Arthur said his philosophy on picking a team included naming your best six batsmen, your best four bowlers then picking a keeper.
"Dan Christian has done superbly well for South Australia. Stats will tell you that he could possibly be in our top six batters," Arthur said.
"If you can get some overs out of your best six batsmen, then that's a bonus."
Meanwhile, the dream run is finally over for man-of-the-moment Warner after he was clean bowled by India in the first over of his Chairman's XI's innings in Canberra.
Warner scored two runs off young quick Abhimanyu Mithun before the Indian hopeful for the MCG got one through the in-form left-hander with his fifth ball to leave the Chairman's XI 1-6 at lunch after just two overs faced.
The 25-year-old Warner, who is captaining the Chairman's XI in the three-day tour match, was coming off consecutive hundreds, in the second test against New Zealand in Hobart and the Big Bash League opener against Melbourne Stars.
India were all out for 269 from 80 overs faced in the opening session of day two, with Victorian Jon Holland the star of the show taking 6-70.
Earlier, youngster Virat Kohli stood tall for India, but they lost their last five wickets for just 62.
AAP
