{{Infobox プロレスラー
| 名前 = グレッグ・バレンタイン
| リングネーム = '''グレッグ・バレンタイン'''<br />ベビーフェイス・ネルソン<br />ジョニー・ファーゴ<br />ジョニー・バレンタイン・ジュニア<br />ブルー・ナイフ
| 本名 = ジョン・ウィスニスキ
| ニックネーム = ザ・ハマー<br />金髪のジェット機
| 身長 = 183cm
| 体重 = 113kg
| 誕生日 = 
| 死亡日 = 
| 出身地 = ワシントン州シアトル
| 所属 = 
| スポーツ歴 = 
| トレーナー = ジョニー・バレンタイン<br />スチュ・ハート<br />ザ・シーク
| デビュー = 1968年
| 引退 = 
}}
'''グレッグ・バレンタイン'''（''Greg Valentine''）のリングネームで最も知られる'''ジョン・ウィスニスキ・ジュニア'''（''John Anthony Wisniski Jr.''、1950年9月10日 - ）は、アメリカ合衆国のプロレスラーである。ワシントン州シアトル出身。ニックネームは'''ザ・ハマー'''。父親は'''妖鬼'''の異名を持つジョニー・バレンタイン。

== 経歴 ==
学生時代にアルバイトとしてプロレスラーをやっていた。1970年、カルガリーにあるスチュ・ハートのハート道場門下生になり、本格的にプロレスを学ぶ。その後ザ・シークの元でもトレーニングを受けている。

若手時代は'''ベビーフェイス・ネルソン'''や'''ジョニー・ファーゴ'''のリングネームでインディ団体で試合をしていた。1974年から父ジョニーもいる団体に移り、ここで'''グレッグ・バレンタイン'''の名前で活動する。当時父のジョニー・バレンタインはまだ現役選手で活躍していたため、父の意向から息子ではなく兄弟と公表していた。（親子の風貌がそっくりだったために、父ジョニーは自分の存在が薄くなるのを嫌がっていたと言われている）

1975年10月に父ジョニーやリック・フレアーが乗ったセスナ機が墜落するという事故が起きる。この時の怪我で父ジョニーは引退。グレッグはこの事件後に、ジョニー・バレンタインの息子であるということを公表し、1976年から、NWAのミッドアトランティック地区で試合を行う。リック・フレアーとのタッグで、タッグ王座を獲得するなど大活躍した。

1978年にWWE（当時WWWF）にも登場。当時のWWWFヘビー級王座（現WWE王座）のボブ・バックランドと抗争し、メインイベンターの地位を確立した。1983年までは、WWEとNWAを行き来しながら試合をしており、NWAでは、フレアーやロディ・パイパーらとの戦いが注目を浴び、US王座を獲得するなどトップ戦線として活躍した。

{{Infobox Wrestler
|name=Greg Valentine
|image=Greg Valentine.jpg
|names=Baby Face Nelson<br>Johnny Fargo<br>Johnny Valentine, Jr.<br>'''Greg Valentine'''<br>The Blue Knight<br>Anthony Premus
|height=6 ft 0 in (183 cm)
|weight=249 lb (113 kg)
|birth_date = 
|death_date = 
|birth_place = Seattle, Washington
|resides=
|billed=
|trainer=The Sheik
|debut=1970
|retired=
|}}

'''John Anthony Wisniski Jr.''' (born American professional wrestler, better known as '''Greg "The Hammer" Valentine'''. He is the son of wrestler Johnny Valentine.

==Career==
===Training===
Born in Angelo "King Kong" Mosca (he lost in around five minutes). Six months later, Wisniski relocated to Detroit to complete his training under The Sheik.

===The Fargo Brothers===
Initially reluctant to take his father's Buffalo and Cleveland based National Wrestling Federation before moving on to Los Angeles and in Japan under Antonio Inoki in 1975 and early 1976.

===National Wrestling Alliance===
In August 1976, Valentine debuted in George Scott's Mid-Atlantic promotion, an affiliate of the plane crash in 1975. He immediately began feuding with Johnny Weaver, who he "retired" with a top rope elbow drop. Valentine's elbow drop was promoted as a deadly move, with tapes of him breaking wooden boards with his elbow shown to the audiences before his debut. 

Valentine then formed a NWA World Tag Team Championships and held the Mid Atlantic Tag Team Championships (between Flair's "cousins" Gene and Greensboro, injuring Gene so badly that he had to be stretchered out. They held the titles until the Andersons defeated them in a steel cage match in the old Charlotte Coliseum. Flair and Valentine regained the tag titles from the Andersons on Baron Von Raschke in 1978.

At the same time, Valentine feuded with Chief Wahoo McDaniel over the Raleigh he defeated Wahoo, breaking his leg in the process. Though Wahoo's legs were too thick for Valentine to apply his signature Figure Four leglock, he managed to break Wahoo's ankle using a Leg/Ankle Suplex. The heel Valentine then began wearing a T-Shirt with the slogan "''I broke Wahoo's leg''" on the front and "''No more Wahoo''" on the back. Wahoo returned on August 9, 1977 and took back the title. Valentine would hold the title once more, defeating Wahoo again on September 10 and losing to Ken Patera on April 9, 1978.

===World Wide Wrestling Federation===
Valentine began working on a casual basis for the World Wide Wrestling Federation, then owned by The Grand Wizard, he was given the gimmick of a methodical wrestler who broke the legs of all his opponents, including Chief Jay Strongbow. In 1979, he faced WWWF World Heavyweight Champion Bob Backlund and fought him to a one hour draw. 

Valentine returned to the WWWF, now known as the World Wrestling Federation, for a year in 1981 and continued to pursue the title. On October 19, he was pinned by Backlund, but then handed the title belt by the dazed referee. The title was held up, and Backlund defeated Valentine cleanly in the November 23 rematch. He also feuded with Pedro Morales, who he "injured" by suplexing him on the floor of the arena.

===National Wrestling Alliance===
Valentine returned to the NWA in late 1979 and asked Flair to reform their tag team. Flair, by then a face, declined. Valentine held the NWA World Tag Team Championships once more with Ray Stevens in 1980. Four days after their victory, the promoter, David Crockett told Valentine and Stevens that he possessed film which proved that the illegal man had been pinned in the tag match, nullifying the win. When Crockett threatened to send the film to Bob Geigel (then the NWA President) who would overturn their victory, Stevens and Valentine attacked him and cut the film up with a pocket knife, destroying the evidence.

Valentine later claimed to have "seen the light", and reformed his team with Flair, who believed that Valentine was now a face. In a tag match against The Iron Sheik, Valentine abandoned Flair, leaving him outnumbered. Flair was beaten, and then Valentine snapped Gene Anderson’s NWA United States Heavyweight Championship, with Valentine finally defeating Flair for the title on Charlotte. He held the title until November 24, when he was beaten by Flair; Flair became one of Valentine's main opponents while in the NWA.

Valentine would hold the United States Championship twice more, renewing his feud with Wahoo in 1982 and defeating him for the title on manager, Sir Oliver Humperdink. Dog Collar Matches, most notably at StarrCade 1983, where Piper pinned Valentine in a non-title match after repeatedly whipping him with the steel chain. The feud was intensified by Valentine's propensity to focus on Piper's ear, which had been injured earlier in his career and would bleed easily. Piper would eventually defeat Valentine on April 16, 1983, but Valentine regained the title on May 1; after the match, where he regained the US Title from Piper, Valentine nailed Piper in the ear with US Title. He dropped the title to Dick Slater on December 14, just before leaving the NWA.

===World Wrestling Federation===
Valentine went to the WWF in 1984, (correctly) predicting that Vince McMahon's plan for national expansion would succeed. His first manager was Captain Lou Albano, and he was later managed by Jimmy Hart.

On WWF Intercontinental Championship, focusing on Santana's injured knee throughout the match. Santana initially thought he had the match won, but had in fact only achieved a two-count. As Santana was celebrating, Valentine rolled him up for the pin and the title. Following the win, Valentine put Santana in the figure four leglock, reinjuring him. While Santana was sidelined having leg surgery, Valentine feuded with WrestleMania. Valentine pinned Junkyard Dog after using the ropes, but Santana came to ringside and informed the referee, who restarted the match. Valentine then walked out, losing the match by count-out but saving his title. Santana eventually healed and fought Valentine in many matches (after he returned to the ring at Wrestlemania). He went on to win the title back on steel cage match in Baltimore, climbing down the outside of the cage and slamming the door on Valentine's head as he attempted to exit. Valentine, incensed over losing the belt, destroyed it in the steel cage, forcing the WWF to get a new Intercontinental title belt.

Valentine would then form a tag team with Brutus Beefcake known as '''The Dream Team''', managed by Johnny V. On the US Express (Mike Rotundo) for the WWF World Tag Team Championship. They held the titles until turning face later on in the night.

Replacing Beefcake with Dino Bravo, Valentine formed '''The New Dream Team'''. Valentine was unhappy about teaming with Bravo, who he felt he had little chemistry with. After the WWF asked him to "kidnap" Matilda, the bulldog mascot of the British Bulldogs, Valentine resigned. He was brought back soon after, with Jimmy Hart as his new manager, but was used in a much diminished role between 1987 and 1990. 

In 1988, Valentine feuded with newly-turned face Don "The Rock" Muraco, after Valentine viciously attacked Muraco's manager, former WWF World Heavyweight Champion "Superstar" Billy Graham. Graham, walking with a cane, tried to intervene when Valentine held the figure-four leglock on jobber Ricky Ataki, after already winning the match.  Valentine then put the figure-four on Graham, who had a plastic hip.

Valentine was entered in the World Heavyweight Championship tournament at WrestleMania IV, where he defeated Ricky Steamboat before losing to Randy Savage, the eventual winner of the tournament. 
In April 1989 he began feuding with "Rugged" Ronnie Garvin. Two weeks after retirement match on ''Superstars of Wrestling'' by reversing a small package and holding on to the ropes. Garvin became a referee until Valentine and Hart managed to have him fired. Garvin then became a ring announcer, and began aggravating Valentine. At SummerSlam 1989 he announced Valentine as being "thirty pounds overweight" as he approached the ring for his match with Hercules, and then announced Hercules as the winner when Valentine cheated to win. Valentine eventually demanded that Garvin be reinstated so that they could fight in the ring.

For some time Valentine had been wearing a shin guard, which he would rotate (so it covered his calf, not his shin) in order to increase the pressure exerted by the Figure Four Leglock. He referred to the shin guard as the "Heartbreaker". Valentine would also (illegally) attach the shin guard to his arm in order to accentuate his elbow drops. In the course of the feud, Garvin countered with a rotated shin guard of his own, which he dubbed "the Hammer Jammer". The feud culminated in a submission match at the 1990 Royal Rumble. Garvin utilized the "Hammer Jammer" during the match, using it to "counter" Valentine's Figure Four Leglock when Valentine applied it on Garvin during the match. Valentine managed to remove the "Hammer Jammer" from Garvin's leg with help from his manager Jimmy Hart after which Valentine systematically wore down Garvin's leg, but eventually lost after Garvin hit him with the Heartbreaker and applied a sharpshooter, forcing Valentine to submit. 

Shortly after, Valentine dyed his hair black and formed a tag team with Rhythm and Blues''' that was managed by Jimmy Hart. Rhythm and Blues feuded with Legion Of Doom, who were by then dominating the tag division.

Valentine turned on Bravo and became a face on Royal Rumble, where he lasted forty four minutes. He was to feud with his former partner, the Honky Tonk Man, but Honky left the WWF before the feud could begin. Valentine lost to Earthquake in a squash match at SummerSlam 1991 by Irwin R. Schyster. He took part in the talent-packed 1992 Royal Rumble, where he attacked his old rival Ric Flair before being eliminated by Repo Man.

===World Championship Wrestling===
Conscious of his diminishing status, Valentine left the WWF and signed with WCW United States Tag Team Championships. After Taylor was fired, Valentine was left without an angle, and eventually resigned in late 1992 when he was asked to lose to Sting.

===World Wrestling Federation===
He reappeared in the WWF at the 1993 Survivor Series under a mask as '''The Blue Knight''' in an elimination match pitting 1994 Royal Rumble.

===Independent circuit===
Valentine went on to tour the Hamilton based International Championship Wrestling promotion and with the George "The Animal" Steele with the assistance of Yokozuna died. He was also involved with the short-lived X Wrestling Federation as an investor and as an in-ring performer. In the 2000s, he began reducing his independent dates in order to pursue a career in real estate. 

On battle royal to become the IWA Heavyweight Champion. He lost the title to AWA Superstars of Wrestling, which toured New England. In AWA Superstars of Wrestling, Valentine regularly wrestled Tony Atlas.

===World Wrestling Entertainment===
On WWE Homecoming, and on gimmick similar to that of Eugene interfered on his behalf, causing the referee to award a victory via disqualification to Conway. He was present at the Retirement Ceremony of his long-time friend, Ric Flair, on the March 31, 2008 episode of WWE Raw.