Puel confirmed that Targett (hamstring) would be out for four months, while there is no clear time frame for Austin's return, with the striker set for surgery on his injured shoulder that should keep him out for three to four months.
Despite losing both players, Puel would not be drawn on his plans for the January transfer window.
"It's always the same question," the Frenchman told a news conference on Friday. "I cannot make speculation about January.
"I say it is always important to stay focussed on the last game before the end of the season."
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Puel is more concerned with getting a result against 10th-placed Bournemouth, who beat the Saints 2-0 in their last encounter.
"Bournemouth have a good team and they are playing well at the moment," said Puel.
"It's going to be a difficult game. Both teams try to play with a good philosophy. I like this about Bournemouth. It will be a good game on Sunday.
"I know the rivalry between the two clubs -- I saw this with many games in France, it's the same in England. We know it's important for the supporters because of the rivalry between the two cities. It always gives a good atmosphere.
"It's important for the fans but it's important to stay with a good consideration about our play and what we can do to win."
Goalkeeper Alex McCarthy is back in training for the first time since Oct. 26 after recovering from a hamstring injury, while defender Cedric Soares, who missed Wednesday's 0-0 draw at Stoke City with an illness, has also returned to the side.
(Reporting by Simon Jennings in Bengaluru; Editing by Toby Davis)
