In Quidditch could the Seeker play other positions?

Question

I don't recall it being mentioned in any of the books, but could the Seeker in Quidditch switch to being a Chaser if needed?

I always thought it was odd that catching the Snitch would net your team 150 points but end the game no matter what. It seemed to me that the seeker would be a more valuable player if they could net their team 150 points but not end the game if they were behind. However, the rules clearly state that catching the Snitch ends the game, regardless of how many points the Seeker's team has.

Is it mentioned anywhere whether it is specifically prohibited for a Seeker to help the Chasers score points so that when their team is behind by more than 150 points they aren't essentially useless? Or would the Seeker just try to distract the other team's Seeker at this point?

Answer 1

In Quidditch Through the Ages, it is said:

However, a fast Keeper may be able to score a goal and then return to his baskets in time to prevent the other team equalising.

That's as much (that I've found) that's explicitly stated, but since the keeper can score, it's likely that a seeker or beater could as well. As for whether someone else could catch the snitch:

A game of Quidditch ends only when the Golden Snitch has been caught, or by mutual consent of the two team Captains.

It seems the rules don't say anything about who has to catch the snitch, it's just in a team's best interest to have a seeker searching for it full-time.

And, somewhat of a sidenote but I looked it up so I'll add it, in the sixth book, when Harry is in detention with Snape for using sectumsempra on Malfoy, Ginny replaces Harry as seeker:

And while he copied out all their various offenses and punishments, he wondered what was going on outside, where the match would have just started... Ginny playing Seeker against Cho...

(HBP, ch.24)

Answer 2

No, there's nothing in the rules that says the chasers were prohibited from doing other stuff.

However, as an old sign on a Texas highway was reputed to state, "If you're driving a car with one hand and hugging a girl with the other, you ain't doing either thing well".

While you're out playing with Quaffles, there's a major risk that the opponent's Seeker will find the Snitch and catch it.

And obviously, not having a bat, a Seeker can't do a very good Beater's job (though, when Dobby enchanted a Bludger to go after Harry in CoS, Harry basically ended up telling Weasley twins to stop worrying about the bad Bludger and he will deal with it WHILE looking for Snitch).

Answer 3

From Wikipedia:

Finally, the Seeker, usually the lightest member of the team and equipped with the fastest broom, is tasked for searching for and capturing The Golden Snitch. Seekers are the only players permitted to touch the Snitch. The seekers, like Harry Potter, are usually small, agile, and stealthy.

I can't say anything about the other positions filling in other roles though