Anthopoulos is most probably the only one with an answer to that question however my guess would be he took a gamble based on his assessment of the situation.
If the achievement highlight is to win a WS and the window of opportunity for any team to win it all is small then it is understandable why he made such a decision. If there was also added impetus from the FO that would point to another reason why he took the gamble when he did rather than continuing along the path of the previously conceived plan. In other words, small window of opportunity in the ALE (won't go into this as it has been said before) this year and next year, players involved in the moves looked great on paper, winning the WS is the crowning achievement, and any other additional unknown factors such as FO's pressure to produce.