Tierney's medical took place on Thursday.
When comparing the two, the Killie man appears to be the better option for Celtic in their search for a replacement for Tierney.
Arsenal will allow more players to leave the club before the transfer window shuts for the rest of Europe's major football leagues on September 2, manager Unai Emery said on Friday.
"Last year, for example, he was very important for players like [Antonio] Rudiger, they were always looking up to him, especially for a team that is trying to play football from the back - like we were, and like Arsenal are".
"I am here to give everything and try to make this club arrive where it deserves to arrive-winning big games and big titles", he said.
"We're delighted Kieran is joining us".
Kieran Tierney claims he was "down the park with friends" when he got the call to seal a transfer to Arsenal, with a frantic dash to the airport undertaken on deadline day.
Trump official revises Statue of Liberty poem to defend migrant rule change
But applicants for visa extensions, green cards or USA citizenship will be subject to the change. Active U.S. military members are also exempt, as are refugees and asylum seekers.
"And I think I got that back from David hence why he ends up moving on to Arsenal".
The 32-year-old was said to have become a disruptive influence at Chelsea's Cobham base and did not train with the team on Wednesday before completing his switch to London rivals Arsenal on deadline day.
The defender only signed a new two-year contract at Stamford Bridge in May but Chelsea are willing to do a deal for a fee of around £8 million.
"And people will be needing to make that shirt their own, as they will all over the pitch".
Earlier, Legit.ng had reported how Pierre-Emerick Aubameyang inspired Arsenal to their first win of the season following their 1-0 victory over stubborn Newcastle United at St. James Park on Sunday, August 11.
"The Premier League is the best competition in the world", he said. "I feel this is a great opportunity for me".
Now, with Pepe on board, they are even stronger going forward and even more formidable opponents for Premier League defences. These are just decisions that I do daily. He has 56 global appearances for Brazil to his name."David has a huge experience and I look forward to working with him again".