Keuchel is currently at 15 innings through 4 starts. At that current rate, that averages to 113 IP through 30 starts (the same amount of starts he made last season). Even if you account for a few good, 'dominant' starts, you also have to take into consideration all the bad ones that will be mixed in between. In last season's 30 start sample, he only made it through 7 innings 4 times, and 6 innings 8 times. With the way he has looked so far this season, he is visibly worse than last season, and is more likely to be headed towards DFA territory. Even with what's left on his contract, don't forget that in 2014 the Sox cut John Danks loose and ate his $14M salary. It wouldn't be unprecedented.