Wells picked up a hamstring strain in Otago's twenty/20 fixture against Northern Districts in Hamilton on November 2.
Initially, it was thought he could be sidelined for up to six weeks, but he has been ruled fit enough to play as a specialist batsman and replaces out-of-form Darren Broom in the middle of the order.
"Darren has missed out and we feel Sam is good enough at the moment to be able to operate as a batsman," Otago coach Vaughn Johnson said.
"He was the encumbent before he was injured and Darren probably hasn't taken his chances.
"Sam has come back a little bit earlier ... but I'm confident he'll come through. The testing the physio has done with him has been pretty comprehensive."
Left-arm spinner Nick Beard is back at 100%. He carried the drinks during Otago's draw with Canterbury at the University Oval last week but probably would have played had there not been some concern about his shoulder, which he injured during the pre-season.
In his absence, offspinner Mark Craig has done a fine job.
He is the team's leading wicket-taker with 13 scalps at an average of 29.15. He has also been more than useful with the bat, scoring 138 at 34.50.
Whether there is room for both will depend on how the surface looks at McLean Park. However, with Wells unable to contribute at the bowling crease, Johnson may opt for four seamers rather than a second spinner.
Competition for that slow bowling spot would have been even more intense had Black Caps offspinner Nathan McCullum been available.
He has not long returned from Sri Lanka and has been given the week off.
"We think that is best for him at the moment after all he has been away for so long," Johnson said. "He'll have this one off and join us up in Auckland."
Otago slumped to a five-wicket loss to Central Districts the last time the sides met. The Volts had been in a strong position but crashed to be all out for 115 in their second innings, losing their last eight wickets for just 26 runs.
The Central attack is led by promising seamer Adam Milne but legspinner Tarun Nethula could pose the biggest challenge.
He has more success against Otago than any other association, taking 23 wickets at 22.30. He took a career-best six for 32 against Otago last summer and backed up with three for 18 in the second innings.
Veteran batsman Mathew Sinclair is on the cusp of a milestone of sorts. He needs another two runs to have scored 2000 runs against Otago. In 20 matches against Otago, he has scored 1998 at 64.45, including seven 100s and 10 half-centuries.
Jamie How also averages in the 60s against the Volts, with four centuries in nine matches.
"They are a strong side.
They're heading the competition at the moment and, on their home deck, will certainly be keen to continue the momentum they've got," Johnson said.
Opening bowler Ben Wheeler is out of the Central team after straining his hamstring in the seven-wicket loss to ND in the twenty/20 clash on Friday night.
Enter English import allrounder Peter Trego, who opens the bowling and the batting for his Somerset county side.
Former Wellington player Andrew Lamb will also come into the squad.
Plunket Shield
Napier, starts today
Otago: Aaron Redmond, Hamish Rutherford, Michael Bracewell, Neil Broom, Sam Wells, Derek de Border (captain), Jimmy Neesham, Mark Craig, Ian Butler, Nick Beard, Jacob Duffy, Blair Soper.
Central: Kieran Noema-Barnett (captain), Carl Cachopa, Jamie How, Andrew Mathieson, Adam Milne, Tarun Nethula, Jeet Raval, Mathew Sinclair, Ben Smith, Peter Trego, Andrew Lamb, William Young.
