Watson suffered a groin injury during Australia's victorious fourth test at the Melbourne Cricket Ground and though he helped the hosts close out the win with an unbeaten 83 on Sunday, was bowled sparingly.
Following the eight-wicket win which extended Australia's lead to 4-0 in the series, Australia coach Darren Lehmann indicated he preferred to pick Watson as an all-rounder rather than a specialist batsman, meaning the 32-year-old might be rested for the Sydney test starting Jan. 3.
The 28-year-old Doolan, a disciple of fellow Tasmanian and former Australia captain Ricky Ponting, replaces fast bowler Doug Bollinger in the squad, with uncapped paceman Nathan Coulter-Nile and all-rounder James Faulkner also in reserve.
Doolan is likely to replace Watson, who has batted at number three, in the lineup if the all-rounder is rested for the dead rubber with Faulkner possibly coming in for paceman Ryan Harris, who has been troubled by knee soreness in the series and was also bowled sparingly at the MCG.
Batting at number six, George Bailey, who was handed his test debut this series on the strength of his form in one-day internationals, is also under scrutiny after managing only 136 runs for the series at an average of 27.20.
His figures are the lowest for any specialist batsmen on either team, barring England's Jonathan Trott, who left the tour after the first test in Brisbane.
"With some players still being assessed by our medical team after four demanding tests, we have decided to add Alex to ensure we have sufficient cover in our batting line-up should it be required," selector John Inverarity said in a statement.
"Alex is a talented player who came under strong consideration for selection ahead of the Ashes series after a string of solid performances in four-day cricket for Tasmania at the start of this season, but also after an excellent finish to last season and we feel those performances warrant his inclusion in the squad of 14 for Sydney."
Australia squad: Chris Rogers, David Warner, Shane Watson, Michael Clarke (captain), Steve Smith, George Bailey, Brad Haddin, Mitchell Johnson, Peter Siddle, Ryan Harris, Nathan Lyon, James Faulkner, Nathan Coulter-Nile, Alex Doolan.