Arsenal have reached an agreement with Chelsea to sign Brazilian defender David Luiz for £8m on a two-year contract.
The 32-year-old centre-back, who signed a new two-year Chelsea deal in May, will have a medical at Arsenal on Thursday.
Luiz has reportedly been involved in a string of rows with Blues chiefs as he tries to force a late move to the Emirates.
Frank Lampard has made it clear to his former team-mate that he is not in his first-team plans, and is apparently willing to let him go in a cut-price deal.
The Gunners have also agreed a £25million fee for 22-year-old Scotland international Tierney.
On Tuesday, Arsenal sold defender Laurent Koscielny to French side Bordeaux for a fee of up to 5m euros (£4.6m) and Carl Jenkinson also joined Nottingham forest on a permanent deal which leaves them light at the back.
Arsenal are now working hard to complete the transfer before Thursday’s 5pm transfer deadline, with Tierney set to fly from Glasgow to London to thrash out personal terms.
It is believed he is set to sign a five-year contract with the Gunners.