Chris Long will remain on loan at Brentford for the duration of their involvement in the Championship play-offs.
Gethin Jones has also extended his loan stay at Plymouth Argyle, who are participating in the League Two play-offs against Wycombe Wanderers.
Brentford still have the opportunity of winning promotion to the Premier League after securing a fifth-place league finish in the second tier.
Brentford play their two-legged semi-final against Middlesbrough on Friday 8 and Friday 15 May. The winners of that tie will then play either Norwich City or Ipswich Town in the final at Wembley on Monday 25 May.
Long, 20, originally moved to Griffin Park at the start of January, with the loan previously being extended twice. He has scored four goals in his 10 appearances for the club, though has not featured since the start of April due to injury and illness.
Meanwhile, Jones, 19, has made six appearances to date during his stint with Plymouth.
The defender’s most recent outing was as a 67th-minute substitute in Plymouth’s 2-0 away win at Shrewsbury on Saturday – a victory that secured their place in the play-offs.
The Pilgrims finished seventh in League Two, setting up semi-final meetings with Wycombe on Saturday 9 and Thursday 14 May.
Should Plymouth progress, the final – against either Stevenage or Southend United – would be at Wembley on Saturday 23 May.