Mentioned earlier about team's leader, serious and rather boring (5)

I believe the answer is:

staid

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'serious and rather boring' is the definition.
I can't tell whether this defines the answer.

'mentioned earlier about team's leader' is the wordplay.
'mentioned earlier' becomes 'said' (I've seen this before. I am not sure about the 'earlier' bit.**).
'about' indicates putting letters inside.
'leader' suggests taking the first letters.
The first letter of 'teams' is 't'.
'said' going around 't' is 'STAID'.

Can you help me to learn more?

(Other definitions for staid that I've seen before include "Serious or sober in character" , "Stuffy, traditional" , "Sedate, decorous" , "Calm, respectable and unadventurous" , "Very conventional and dull" .)

I've seen this clue in The Telegraph.

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