Agree about the new bat being passable (3,3)
I believe the answer is:
not bad
'passable' is the definition.
(thesaurus)
'agree about the new bat' is the wordplay.
'agree' becomes 'nod' (I've seen this before**).
'about' is an insertion indicator.
'the new' indicates anagramming the letters.
'bat' is an anagram of 'tba'.
'nod' going around 'tba' is 'NOT BAD'.
'being' acts as a link.
(Other definitions for not bad that I've seen before include "fair" , "Passable" , "Grudging praise" , "could be OK" , "So-so" .)