。
That team is packed with formidable players.
Literal
That team [topic-は] tough-warriors gathering [copula-だ].
つわもの (強者) 'formidable person / warrior / master' is a literary noun for someone powerful. ぞろい (揃い) 'a full set of / lineup of' means every member is a formidable player. つわものぞろい 'packed with tough players' is a compact evaluative compound. A concise, punchy sports/competition assessment.