Daniel Flynn: still not back on top of his game after losing two teeth at Old Trafford © Getty Images

New Zealand's line-up for the third Test against England at Trent Bridge on Thursday could feature as many as three changes from the side that lost at Old Trafford last week, as the Kiwis attempt to battle back into a series that they looked to have in their control at the midway point of the second Test.

After missing the Manchester match with an upset stomach, the teenaged seamer, Tim Southee, seems a sure bet to reclaim his place at the expense of Iain O'Brien, but it is the form and fortunes of two of New Zealand's middle-order batsmen, James Marshall and Daniel Flynn, that will come in for the most scrutiny in the coming days.

Flynn, 21, suffered an horrific facial injury on the second day at Old Trafford, when he ducked into a James Anderson bouncer and was forced to retire hurt with two missing front teeth. He did not reappear in the second innings, and though he played during the warm-up match against Northamptonshire at the weekend, he was a notable failure, lasting just 12 balls in two innings.

Flynn has been enduring several bouts of dental surgery between innings, but his coach, John Bracewell, described him as a "tough rooster" and backed him to resume his two-Test international career sooner rather than later. Even so, there is so much at stake in the third Test, and Flynn's confidence took such a battering, that the steady presence of Peter Fulton could yet be called upon in his place.

"I would have liked to see Daniel spend more time at the crease getting his confidence," Bracewell told the Press Association. "There's nothing like being in the middle, and the hustle and bustle of it, to get yourself back on the bike. He's a tough rooster and he will recover very quickly, it's just whether we match up Peter Fulton's form against him and James Marshall."

Fulton was dropped ahead of England's recent tour of New Zealand after failing in the one-dayers, but Bracewell had some encouraging words after watching him return to form with a confident 57 against Northants. "He looked, for the first time in a long time, in pretty good nick," said Bracewell. "He looked to be hitting the ball crisper in the areas we wanted him to hit the ball, and he certainly comes into contention."

All of which heaps extra pressure on Marshall, who started the tour well with a century against Essex to cement his place at No. 3 for the first Test, but since then his form has been on the wane. He managed just 52 runs in his first four Test innings - a tally that included ducks at both Lord's and Old Trafford - and he managed only 13 runs for twice out at Northants.

"James scored a brilliant hundred in trying conditions against Essex earlier in the tour, and I don't think you can discount those sorts of innings," said New Zealand's vice-captain, Brendon McCullum. "The selectors will just have to come up with the best team that can go out and level this series for us."

Even so, McCullum's own success as a No. 5 batsman means that New Zealand could be tempted to call up their specialist wicketkeeper, Gareth Hopkins, who furthered his own cause with a fighting 63 at the weekend. That route, however, would require a promotion for both Jacob Oram and Daniel Vettori, who have played important roles at No. 7 and 8 respectively.

Whatever line-up New Zealand settle on, they will not be dwelling on their missed opportunity in the second Test. "In a strange sort of way, Old Trafford was a confidence-builder for us," said McCullum. "We put ourselves in a position where we should have won the Test match, and that was something that heading into the Test, we may not have whole-heartedly believed.

"To be able to do that and then go to Northampton and put on a performance like we have - batting so clinically - was pretty good. It's a step forward. It certainly hasn't rectified all our issues, but in my mind it is a step in the right direction."