Of course, it all worked out, so it's easy to support this decision now. Still, I was stoked when I saw him warming up and thought it was a great decision for several reasons:
1. I don't trust Tazawa to hold the lead.
2. They need to conserve Koji.
3. Lackey has two days off before Game 6. It's like he's getting his bullpen work in as scheduled, but under real game conditions. Plus, his workload in Game 2 wasn't overly heavy. He should still be effective in Game 6.
4. It was convenient in double switching the pitcher's spot with Napoli after they decided to pinch run for Papi. They could have switched around other players, but they wouldn't want to have to have Koji hit if they had to bring him in early in the 8th if Tazawa looked vulnerable (a strong possibility).
5. Outside of Koji, he was clearly the best man for the job. Outside of Tazawa, we're looking at a choice between Workman, Morales, and Dempster. Workman is not a bad choice, but he threw 30 pitches in Game 3. He will likely be needed for Game 5 and beyond. Plus, Lackey has already proven himself against this lineup. The only question was could he do it in an unfamiliar role.
Lackey has already been to the top of mountain. He may very well carry his teammates with him there again.