Shadrag (from Caves of Chaos) as a PC?

After completing Cave H, the Bugbear Lair, in my last session, one of the players asked of they could play Shadrag (the rebel bugbear) in a future session.  

On freeing him from prison, they outfitted him with some of the equipment stripped from fallen bugbears, and he joined them for the rest of the session, giving information on the bugbear leader and the location of the common room.

I was going to have him killed in the common room (he ran in and fought on the front lines), but the ranger and the wizard really liked him and did their best to heal him.  Needless to say, they were successful and he helped them in killing the leader's mate, while the leader escaped into the Minotaur cave.

Would you guys run with an idea like this?
Yes, definitly. The character has a story bounding to to the rest of the party that create an incentive for him to stick around (and to mbe played as a character OOC)

If you are concerned with mechanical you can use an Elf chassis or make up one roughly based on the monster statblock. Here's an exemple: (The descriptor is from 4E)


Big tough goblins that love to fight, bugbears are the
champions, picked guards, and muscle for more clever goblins.
Bugbears take whatever they want and bully others into
doing their work. They hunt for food, eating any creature they
can kill—including other goblins.
As a bugbear, you have the following statistic:
Size: Medium.
Low-Light Vision: Darkvision 60’
Stealthy: You are trained in the Bluff and Sneak skills.
Languages: You can speak, read, and write Common
and Goblin.
Ability Score Adjustment: Your starting Dexterity
Score increases by 1.
Speed: 30 feet.

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