The problem with the Red Sox' bullpen isn't really the bullpen. As many have said here, it's that they have almost no starters who go deep into games.
Crawford: 17 starts, 3 games with 6.0 ip, 0 games with >6.0 ip
Bello: 22 starts, 6 games with 6.0 ip, 8 games with >6.0 ip
Paxton: 18 starts, 5 games with 6.0 ip, 2 games with >6.0 ip
Sale: 15 starts, 2 games with 6.0 ip, 2 games with >6.0 ip
Houck: 15 starts, 3 games with 6.0 ip, 1 game with >6.0 ip
Whitlock: 10 starts, 0 games with 6.0 ip, 4 games with >6.0 ip
Pivetta: 11 starts, 2 games with 6.0 ip, 0 games with >6.0 ip
So out of these 7 starters: 108 starts, 21 starts with 6.0 ip (19.4%), and 17 starts with >6.0 ip (15.7%).
So that means that in 38 of 108 starts (35.2%), they go 6 or more innings. And that means that for nearly 65% of their starts among these guys (and this doesn't even take into consideration the guys who are "openers") they're not even getting through 6 innings. That puts a TON of work on the bullpen. And they burn out over time. There's just no way the bullpen can pitch all season long at max effectiveness working that many innings. The starters HAVE to go longer. And if these guys can't do it, they need better starters.
Of course, some of this is an organizational philosophy regarding not wanting starters to pitch to lineups a third time. We know the numbers on that - so there's merit to that philosophy. But it does come with a great cost - burning out the bullpen over the 162 game grind.
Crawford: 17 starts, 3 games with 6.0 ip, 0 games with >6.0 ip
Bello: 22 starts, 6 games with 6.0 ip, 8 games with >6.0 ip
Paxton: 18 starts, 5 games with 6.0 ip, 2 games with >6.0 ip
Sale: 15 starts, 2 games with 6.0 ip, 2 games with >6.0 ip
Houck: 15 starts, 3 games with 6.0 ip, 1 game with >6.0 ip
Whitlock: 10 starts, 0 games with 6.0 ip, 4 games with >6.0 ip
Pivetta: 11 starts, 2 games with 6.0 ip, 0 games with >6.0 ip
So out of these 7 starters: 108 starts, 21 starts with 6.0 ip (19.4%), and 17 starts with >6.0 ip (15.7%).
So that means that in 38 of 108 starts (35.2%), they go 6 or more innings. And that means that for nearly 65% of their starts among these guys (and this doesn't even take into consideration the guys who are "openers") they're not even getting through 6 innings. That puts a TON of work on the bullpen. And they burn out over time. There's just no way the bullpen can pitch all season long at max effectiveness working that many innings. The starters HAVE to go longer. And if these guys can't do it, they need better starters.
Of course, some of this is an organizational philosophy regarding not wanting starters to pitch to lineups a third time. We know the numbers on that - so there's merit to that philosophy. But it does come with a great cost - burning out the bullpen over the 162 game grind.