(Saw this post after the other one on the same subject)
At the moment, I'm a bit worried about both Ortiz and Penny. Both have huge potential (with Ortiz having slightly more), but their control has looked off so far. Ortiz has a k/bb ratio of 4:3, while Penny's looks even worse at 1:1. Sure, it's early, but I am starting to worry. It's certainly not a good start to what should have been a breakout campaign for both. Ortiz has given up more than his share of homers, too, although that isn't really statistically significant.
Clement is just the opposite: a guy who had lots of chances in the past, blew them, and is surprising everyone so far. He hasn't been getting wins, but he's looked spectacular at times.
My feeling would be to keep Clement and Penny. I think it will be at least another month from now before we figure out in which direction these pitchers are headed (or to which team Higginson may be headed?) - keeping two of them would spread the risk (and I actually like Clement slightly more than Ortiz at the moment).
The bottom line, however, is that in a situation like this where nobody can be sure of the outcome, you should go with your instincts. At this point, you could make excellent points for ranking any of these pitchers ahead of the other two - go with who you think will be best. If you agree with timkell and think Ortiz has the best chance of reaching his potential, you should definitely accept. If you're unsure or like one of the others, decline (assuming roster considerations, as mentioned in the other thread, aren't much of a factor).
One thing to consider would be waiting a couple more days before making a decision, and paying close attention to these pitchers' next starts. Plus, there will be more time for others to add their input here...