Batum isn't playing that great either, Martell is just in a huge slump and therefore, is not playing. There is no "experiment", he played well when he was needed to fill in due to injuries earlier in the year. Now that more of the regular rotation players are in, he's getting pushed back. Trading him for nothing or a second round pick isn't going to do much really, I'd rather have an inconsistent Martell than stashing some schlub in Europe that will never see the court. He's fine as a backup SF (but again, right now he's not).
He's actually been playing much better than Rudy this year.
Actually, Batum has played great. Or at least borderline great.
In terms of win score per 48 minutes, which is a tremendous stat to track overall play, he's the 3rd best player on our team, after Oden and Roy. He's playing at near all-star level, he just hasn't yet gotten the minutes.
Webster is right at the league average, which is his career high. Fernandez slightly below average this year, but was at near all-star level last season. I don't think Webster is playing 'much' better than Fernandez, but he is slightly better this season. But the one thing that nobody can argue with...Webster is mentally fragile as the OP said.
Trading Webster would be a good move, not JUST to get some Euro schlub, but to clear more minutes for better players like Batum and Fernandez, assuming Fernandez returns to form.
Side note, we've traded most of the players who are below average on the list of win score per 48 minutes over the last 3 seasons. I think it's a number that Pritchard really looks at, or at least a great number to measure the value of a player on the court.
Over the last 3 seasons, here are the players who have finished a season with below league average in win score per 48 minutes.
Steve Blake
Travis Outlaw
Martell Webster
Jarrett Jack
Taurean Green
Von Wafer
Jerryd Bayless
Channing Frye
Raef Lafrentz
Sergio Rodriguez
Ike Diogu
Just 2 of those players are still with us. Now this season, Fernadez, Przybilla and Juwan Howard are in danger of finishing below average with Webster a possibility to drop below average if he continues his sucking ways.
Not a good sign for your Portland future if you're on that list.