I mean, if we're just going to pull out the negatives in all of our players and only the positives in Felix, then sure, it's going to look like we need to tack someone else on.
But Ellsbury was the MVP last year (no, Verlander was not IMO). He was a 30/30 guy who hit .320. He got hurt twice for playing hard, not because he has a bad back. He went all out for a pop up and went in hard at 2B. Not anything you can hold against him. He had 5 broken ribs misdiagnosed by the Red Sox medical staff in 2010, again, not his fault, they cleared him to come back and play and he aggravated his injury. This year, they're being cautious with him, fine, but it's not like he's the one holding himself out of the line up.
It's well, well, well beyond ridiculous to call Ellsbury "injury prone". Injury prone is when guys have RECURRING INJURIES TO A SPECIFIC AREA THAT DOESN'T EVER HEAL. That is not at all what we have with Ellsbury. Two freak accidents.
And as for Lester, he's had a tough season this year, fine. But his career ERA+ (park adjusted) of 124 is almost identical to Felix's ERA+ of 127. I'm not sure how you can justify giving up more than Ellsbury to make the deal fair. In fact, if anything, the Mariners would likely have to give up a prospect in the deal. To say the Red Sox would have to give up a top prospect along with Ells/Lester? That's absolutely ridiculous.
As for signing Ellsbury, you do realize that Felix is due $58mm over the next 3 years, whereas Lester is due $24mm over the next 2. So that's a $34mm savings right there. They also could depart ways with Ichiro, whose contract is up this year. He was making $17mm. The money saved from those two alone would more than allow the Mariners to sign Ellsbury, and let's be honest, they've got money out the ass. The owners of the Mariners are this little company called Nintendo, maybe you've heard of them? They have money to spend.
The Mariners are in desperate need of offense. They picked up Montero this year. They have Ackley. And they're still hitting .197 at home this year. They need a guy who is electric, someone who can generate offense, and in order to get that guy, they have to do it via trade because nobody is going to sign there as a FA.