"We looked at all the other [New Zealand] franchises and they were full of props and we actually wanted Pauliasi to stay and then we got blindsided by the Australians, really. That was just the Australians coming in and picking off our players, which is a little bit unfortunate," Kirwan said.
"We thought that Ofa Tu'ungafasi might have been at more risk ... We're a bit disappointed about that."
Kirwan said Manu understood his decision and was happy with it, but added: "Obviously what happened was that was known by his manager and the Australians and that was the end of it."
However, Kirwan's disappointment over losing Manu could be counterbalanced by the signing of hooker Quentin MacDonald from the Crusaders, although the Blues coach yesterday refused to confirm that.
Kirwan is likely to rate Tom McCartney as his top-ranked loosehead prop, with the durable player's former role as back-up hooker likely to go to MacDonald, a New Zealand age-group representative who failed to kick on at the Crusaders mainly due to injuries.
The addition of MacDonald would be a coup, but the Crusaders are likely to be satisfied that in young Canterbury pair Ben Funnell and Codie Taylor they have adequate back-ups for Corey Flynn.
Kirwan is also understood to have signed Tasman 24-year-old loosehead prop Tim Perry, yet to make his Super rugby debut, as a replacement for Manu.
The coach's starting front row of McCartney and All Blacks Keven Mealamu and Charlie Faumuina is excellent, but a lack of depth could be exposed if either is injured.
Perry and Tu'ungafasi are untested at Super rugby level, with Angus Ta'avao, another Auckland prop, struggling at times last season, especially against the Crusaders in Christchurch, where he started but was replaced after only 28 minutes. Tevita Mailau, the Blues' other prop last season, is now playing in France.
Kirwan, however, is putting on a brave face, despite the loss of Woodcock, and of fellow All Black Ma'a Nonu to the Highlanders.
"We've done a lot of research into it [front row stocks] and we're really positive we've got it covered."APNZ