Aguero, who has netted 257 goals in 384 appearances and won four Premier League titles, one FA Cup and five League Cups at the club, is set to leave when his contract expires.
"I don't know what's going to happen but at these prices we're not going to buy any striker," Guardiola told reporters ahead of Saturday's league trip to Leicester City.
Welch has previously officiated men's matches in the National League as well as elite women's matches such as the FA Cup final in 2017, but on Monday she will set a new benchmark for female referees in English football.
It shows that there is a real opportunity to young girls who are wondering if to they are to take the whistle or are already referees they can aspire to be an EFL referee or like Sian Massey-Ellis operating in the Premier League.
Werner, who arrived at Stamford Bridge from RB Leipzig in June, made a bright start under former boss Frank Lampard, scoring eight goals in his first 13 appearances in all competitions.
At the moment I can see that his face is a bit closed, I can see that the weight is on his shoulders.
The Gunners' defence of the trophy they won by beating Chelsea last August ended with something of a whimper as Mikel Arteta's side struggled with repeatedly sloppy defending.
Arsenal could have fallen further behind with home striker Danny Ings going close for the hosts on several occasions.
We go again, there's no doubt about that. When things don't work out on the pitch as we want them to, there's an issue.
Confidence is not naturally given to normal people so some things have to work out to build confidence. It didn't work out in the final third for us in the last few games.
Victory for Shandong denies Jiangsu a league-and-cup double after Cosmin Olaroiu's side had won the Chinese Super League in a playoff with Guangzhou Evergrande last month.