Mike Agar played in WA's last Shield game against QLD up at the Gabba a month ago scoring 72 with the bat and taking 0/89 & 1/16 with the ball. He also played in the PM XI vs WI in Canberra before that but they were pretty much his only first class red ball games in a year or so.
At the end of the day he has only 9 Test wickets at 52 in 5 Tests and averages about 42 with the ball in Shield cricket as well which are not the sort of numbers to keep Test batsmen (let alone Indian) up at night!
I think he was probably picked on his all round ability as much as his spin variety for Sydney due to Green missing with injury, but his length (he is either to short or too full) and line are not Test standard.
On another point how on earth did Warner win the man of the series?
He scored 213 runs from 4 innings with 3 of those innings contributing 0 (Golden Duck), 3 & 10!
I had Head, Cummins, Smith, Lyon, Carey, Khawaja & Green all ahead of him.