Q: Is it correct to use a comma before “and” in these sentences? (1) “The wide-eyed, baby-faced Beaubois continues to work hard in practice, and has begun to make his mark in a crowded and deep rookie class”; (2) “The Bobcats have spent much of the season with the NBA’s best defense, and are likely to make the playoffs”; (3) “Despite the setback, however, Milwaukee remains in solid position to nab a surprise playoff berth, and could find itself seeded as high as fifth.” If I’m not mistaken, a comma may only be used before “and” to separate two independent clauses.
A: It’s sometimes legitimate to use a comma in a sentence in which two verbs share a single subject. We might do this, for example, if the sentence is long and complicated, or if a comma would avoid confusion.
So, yes, it may be proper to use a comma before “and” to separate parts of a sentence that aren’t independent clauses. A clause, as you know, is a group of words with its own subject and verb.
Here’s how The Chicago Manual of Style (15th ed.) describes this use of the comma:
“A comma is not normally used between the parts of a compound predicate – that is, two or more verbs having the same subject, as distinct from two independent clauses – though it may occasionally be needed to avoid misreading or to indicate a pause.”
This is the example given in the style guide: “She recognized the man who entered the room, and gasped.”
If we were editing those sentences you quote, would we have kept the final commas? Yes and no. We could make a case for the commas in sentences 1 and 3, which seem to need pauses, but not in #2.