One obvious suggestion could be Ryan Dempster of the Cubs. He has an 0.95 ERA, the lowest ever for a pitcher who has yet to win a game through five starts. He is hurt by being on a low-scoring team. But if he came to Boston, he could thrive.
Dempster's ERA is now 1.02, but it's pretty much the same as 0.95. Dempster also has a 2.13 FIP and 2.78 xFIP. His ERA ranks best in MLB while the FIP is 4th best and he's 7th in xFIP.
He's striking out a career high 26.9% of the batters he faces and walking a career best 7.5%.
He's been a little lucky on balls in play as his BABIP is just .218 and he's allowing fewer than 4% of his fly balls as home runs. Both rates will regress. So will the strikeouts and walks and as a result the ERA, FIP and xFIP too.
ZIPS projects just under 140 more innings from Dempster and a 3.76 FIP. That amounts to close to 3 WAR per 200 innings so over 140 more he'd be worth 2 WAR. He's owed roughly $11 million the rest of the season and his value based on expected WAR is $10 million. So the Cubs would have to kick in a million bucks to get a deal done and wouldn't receive much at all in return.
Then there's the issue of whether or not Dempster would waive his no-trade clause and I'm guessing he would not. His daughter's doctor is in Chicago and there's little chance his family would move with Dempster for a partial season in Boston. I doubt he'd be willing to be away from the family given his daughter's disorder.
It might make some sense for Boston to go after Dempster, but I'm not sure the Red Sox are really worrying too much at this point. They have a good team and while they've suffered a lot of injuries, they're going to be better than they've shown to this point. They probably aren't going to the playoffs either. Ryan Dempster won't change that.
I think a lot of fans are going to be upset when the Cubs don't trade Ryan Dempster this season. For one thing, I don't think he's going to accept a trade and secondly, I don't think the Cubs will want to trade him. I actually think they keep him around and negotiate a 2-year deal after the season. I think Dempster will be in a Cubs uniform next season and probably starting on Opening Day for the third year in a row.