private fellow

"The Drunkard's Walk" を読んでいます。　
Maris, on the other hand, was a gruff, private fellow, an underdog who had never hit more than 39 home runs in a year, much less anywhere near 60.
...
Maris broke Ruth's record with 61.
野球は興味がないのでベーブルースしか知りませんが、このMarisは "private fellow" とあり、人付き合いの悪い人間かと推測しますがどうでしょう？
・Macmillan Dictionary: a private person does not talk to other people about their personal life and their feelings
・American Heritage Dictionary: Placing a high value on personal privacy: a private person.
・Collins English Dictionary: (of a person) reserved; uncommunicative
だいたい当たっていたようです。