Are there tennis players who are as big or buff as football players (assuming we're talking about the respective "players" from the PROFESSIONAL ranks)? No.
Big as e.g. football linemen? No, no, no, no, no.
Buff as e.g. football "skill position" players? No, no, no, no, no.
Fast as e.g. football "skill postition" players? No, no, no, no, no.
Athletic as e.g. football "skill postition" players? No, no, no, no, no.
That's why THESE guys are tennis players and why THOSE guys are football players. The "football-esque" jocks in tennis may exist but they're needles-in-haystacks.
Sorry, but that's the truth. As fast as Rafa is (and he's got a great motor), there are a slew of D.B.'s, receivers, running backs, etc. who'd blow his doors in, sprint-wise.