Slav, we aren't talking about 8 and 9, we are talking right now about 6-9. When Betts comes back, you are looking at a lineup of
1. Betts RF
2. Benintendi LF
3. Martinez DH
4. Moreland 1B
5. Bogaerts SS
6. Devers 3B
7. JBJ CF
8. Nunez 2B
9. Vaz or Leon C
If Pedey cannot come back his usual self (which is looking more likely by the day), then you are looking at a black hole in your 6-9 spots. Add to that the fact that Moreland is playing way over his head and there isn't much room to go up for Beni, Betts or JDM and likely a continued current approach of Bogaerts, then your top 5 is likely going to decrease at least a touch going forward. Your top 5 is maxed and likely looking at slightly less productivity over the next 100 games. Currently, your 6-9 spot has given you this:
#6- .234/.310/.414
#7- .235/.292/.332
#8- .204/.265/.317
#9- .236/.300/.349
That's abysmal, but place in the order changes with the pitchers faced. The better idea is to look at the positions
As C- .589- 13th in AL
As 2B- .626- 10th in AL
As 3b- .662- 14th in AL
If it weren't for the fact that Beni has hit like an MVP when he plays CF (1.104OPS vs .827OP as LF), the position would be a graveyard as well as JBJ (if he qualified) would be the 10th worst offensive player by OPS in all of baseball. When JBJ plays, you are adding a .603OPS to the positions noted above.
I get that seasons past have seen teams with lesser offensive profiles win the title. But looking at those teams...
2017 HOU- Marwin Gonzalez, Carlos Correia and Jose Altuve were .900+ in OPS. Bregman, Springer, Reddick, Gurriel, and Marisnick were .800+. McCann was .759 at a premium position. That's 9 guys. Their backups by the postseason were a well past his prime Beltran (who didn't play much in the postseason) and Aoki who's game is to get on base and steal some bases, not hit for power
2016 CHC- Rizzo and Bryant were .900+. Zobrist, Fowler, and Contreras (who ended up catching the lions share of playoff games) were .800+. Baez, Russell, and Soler were .730+, which isn't great, but they did pop 47HR between them in what amounted to 2 full time positions. The only regular come the postseason who remained in the lineup and was abysmal (sub .700OPS) was Heyward.
2015 KC- Entirely different type of roster construction. They had above average speed throughout the lineup which Boston doesn't have beyond 2 players (Beni and Betts). They stole some bases, but also took the extra base better than anyone. They played defense better than anyone. They had a bullpen that could come into a game with 5 innings to go and shut teams down. But looking at their lineup... They had 6 guys post OPS+ of 119 or better (Zobrist, Hosmer, Moustakas, Gordon, Cain and Morales). Escobar had no business batting 2nd, I agree there, but he did chip in with 17 stolen bases. Their catcher didn't walk at all, but did pop 21HRs in Perez. Their RF spot was a mess until they decided to put Dyson out there who stole 26 bases in half time. While they had their warts offensively, they had more depth in their lineup. Guys who weren't OPS'ing high could either hit for power or steal some bases. You don't have that with Nunez, Leon, or JBJ right now. Devers hitting over 20HRs might be enough of a saving grace to justify his spot
2014 SF- Every single guy in their lineup was OPS+ of 104 or higher. They weren't filled with amazing hitters aside from Posey, but they were consistent throughout. They also had the best pitcher I have ever seen in a postseason win them 3 games in the world series and only need the rest of the team to figure out one win