Manchester City are on the verge of signing Arsenal winger Samir Nasri for around £25 million, according to widespread reports.
The deal could be finalised in the next 24 hours, with Nasri due to undergo a medical in Manchester before signing a five-year deal.
Nasri, who has scored 27 goals in 124 appearances for Arsenal since leaving Marseille in 2008, is into the final year of his contract and has rejected a new deal at the Emirates.
The transfer of the France international will take Roberto Mancini's summer spending to £77 million. City have already landed Sergio Aguero for a club record £39 million and splashed out a combined fee of £13 million on Stefan Savic and Gael Clichy.
Nasri would become the second high-profile departure from Arsenal this week after captain Cesc Fabregas finally rejoined boyhood-club Barcelona.
"We have to win something this season,'' Walcott said. "It is important to have a mixture of experience and young players - but the boss knows what he is doing. He has picked up great players before. Only time will tell what he is going to do.
''Of course the players sometimes think, 'What's going on?' We've had a couple of injuries and we have to hope they are not too bad. We have got a fairly big squad but we don't want the squad to get lower and lower.
''The boss knows what he is doing and hopefully those players will be fit and ready to go anyway. I'm sure the boss has got players coming in. I don't know, but if you sell one of your best players... I'm sure he's got some options coming in.''