Craig left the field towards the end of the third day and was unable to bowl yesterday.
Volts coach Dimitri Mascarenhas said the team will assess his injury during the next few days.
''He has a bit of a knee complaint. We're not sure how bad it is yet,'' Mascarenhas said.
''We'll see how he goes during the next few days before our home game.''
Otago hosts Auckland in Dunedin next week and will be keen to force a result following a frustrating match with Wellington.
Much time was lost in the match due to poor weather but Mascarenhas felt his side did not play well enough to secure an outright result.
''We thought we might have a chance to try to do something [yesterday] but it wasn't to be. They batted pretty well in the first session.
''At the end of the day we did not bat or bowl well enough to force a result.
''It is disappointing but we've come out of it with more points than them and we played pretty well.''
Right-arm pace bowler Jacob Duffy had a tidy match. He picked up five wickets for the match and bowled nine maidens in Wellington's second innings.
''Jacob is bowling really well. He bowled a good line and length. He swung the ball, got movement and got good players out. He has come along really well this year.
''I'm very happy with his progress and he just keeps getting better as well.''
Wellington resumed on 70 for one with an overall lead of 116.
Veteran opener Michael Papps, who earlier in the game claimed his 200th dismissal, went on from his overnight score of 44 to post his 26th first-class hundred.
It came off 175 balls and included 14 fours. He was eventually out for 110 when he got an edge through to the keeper.
With Wellington's lead approaching 300 runs, and no sign of a declaration, Otago captain Aaron Redmond brought batsman Hamish Rutherford, Michael Bracewell and Ryan Duffy on to bowl and even wicketkeeper Derek de Boorder took off his pads to have a bowl before the tea break.
Otago used 10 bowlers in Wellington second innings. Had Craig been fit, everyone might have had an opportunity at the crease.
Mercifully, both captains agreed to an early end during the tea break.
Wellington had reached 255 for five with Alecz Day undefeated on 32 and Tom Blundell not out 33.
• Auckland and Canterbury are involved in a cracking encounter at Colin Maiden Park. Canterbury secured a 46-run first-innings lead but a rapid century from Colin Munro (137 from 138) has set up an intriguing final day's play.
Auckland will resume on 361 for five with a lead of 315.
