Emmanuel Adebayor, Wayne Bridge and Roque Santa Cruz all departed Eastlands in the search of regular first-team action, along with three of the younger members of the City squad who were given first-team exposure in the Carling Cup earlier in the campaign.
But boss Mancini is now bemoaning a lack of bodies as a reason for some of his side's more stuttering performances in recent times, including their 2-0 first-leg defeat to Dynamo Kiev in last week's Europa League last-16 clash.
Numbers game: Mancini prepares his injury-hit squad for their crunch Europa League clash on Thursday
City try to overturn that deficit at Eastlands on Thursday, still using the same group of players they have been forced to rely on since fixture congestion first became a problem in the middle of January.But Mancini is adamant he has not been the architect of his own downfall.
'If there are some players who want to leave because they wish to play every game, it is difficult,' he said.
'Should two or three players leave the club, you could buy two or three more.
'But we didn't think four or five important players would get injured in the space of 20 days.'
Shay Given, James Milner and Adam Johnson have all been sidelined for extended periods, with a succession of minor injuries to be taken into account as well.
In addition, Kolo Toure is suspended indefinitely pending an inquiry into his failed drugs test, robbing Mancini of another valuable option.
'When you become a top club you should have 25 players available in every game,' he said.
'If you watched the game between Manchester United and Arsenal in the FA Cup, United changed eight players.
'When you play every three days, you need to change five or six players, minimum.'
Loan rangers: Mancini defended his decision to let Santa Cruz, Adebayor and Bridge leave the club in January
In fact, United manager Sir Alex Ferguson changed six. It could also be argued that if Mancini had made more use of his squad earlier in the season, when he kept using the same group of players, the disaffected ones might have been encouraged to remain in the fold.
In addition, FA Cup draws against lower league opposition in the form of Leicester and Notts County helped fill what should have been a spare couple of midweeks with replays.
City have been left to play seven midweek fixtures out of nine since the middle of January and one of the others was reserved for international matches.
Little wonder victory tomorrow could be regarded as something of a double-edged sword.
'If we win and reach the quarter-final, we are playing twice a week until the end of the season,' he observed. 'This could be a big problem.'
Not that Mancini is prepared to countenance defeat at this stage, even if a Kiev side marshalled by a resurgent Andriy Shevchenko look set up perfectly to hit their hosts on the counter-attack at Eastlands.
Danger man: City are trailing 2-0 to Kiev after ex-Chelsea flop Andriy Shevchenko scored in the first-leg
All the more reason to lament the absence of Johnson, who has started training after almost two months out with an ankle injury but will not be considered until after the international break.
'We do not have another player like Adam,' said Mancini.
'When he is on the pitch, he can change a game, just by the way he plays.'
The most obvious alternative is Shaun Wright-Phillips, although for much of the year he has been troubled by a back complaint that has restricted his availability.
'Shaun only worked for five days last week because his back was hurting,' revealed Mancini.
'Now I hope he can play and also change the games for us in the next two months.'
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