No way. After all, the summoner of Assassin EMIYA is, of course, Shirou Emiya. He has the potential and skill to fire Noble Phantasms from a bow at ludicrous ranges, yet at this point still lacks the skill to do so with the proficiency of a Servant. Furthermore, he has the perfect catalyst to summon EMIYA with him at all times.
'But wait!' Some of you cry, unable to recognize my genius. 'We saw Shirou summon Rider, and he wasn't in position to shoot us with swords!' But you have been deceived. After all, the competent magus, who struck a hard bargain for Avalon before finally relenting, could only be Tohsaka Rin under a clever disguise. After all, 'he' summoned Lancer without a catalyst, and did not Lancer say that Rin would be his ideal master? Check and mate.