Kris Boyd, John McGinn & Celtic's Scott Brown & James Forrest up for PFA award
Kilmarnock's Kris Boyd and Hibernian's John McGinn stand between Celtic and a fifth consecutive PFA Scotland Premiership Player of the Year award.
Celtic captain Scott Brown and fellow midfielder James Forrest are the others on the shortlist with their side on the brink of a second successive treble.
The 34-year-old Boyd has never won the award despite having led the top-flight scoring charts four times.
Midfielder McGinn has established himself as a Scotland squad regular.
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Celtic left-back Kieran Tierney is in the running to win the Scottish Professional Football League Young Player of the Year award for a third year running.
Aberdeen centre-half Scott McKenna, Rangers striker Alfredo Morelos and St Mirren winger Lewis Morgan, who is on loan from Celtic, are the other nominees chosen by their fellow professionals throughout the four senior divisions.
Morgan, who was sold to Celtic in January and loaned back to St Mirren as they headed towards the Championship title and promotion, would be the first to win the award while playing outside the top flight.
Striker Michael Higdon, then of Motherwell, in 2012-13, and midfielder Steven Davis, for his Rangers performances in 2009-10, are the only non-Celtic players to have won the senior player of the year award in the last 12 years.
Boyd, who has 18 Scotland caps and whose 16 goals is the most in the Premiership this season, lost out to then team-mate Davis in 2010 and was last among the nominations in four years later.
Now in his second spell with Kilmarnock, the veteran striker has thrived under Steve Clarke's managership and helped his side reach the top six for the first time in seven years.
McGinn, who was PFA Scotland's Championship Player of the Year last season, helped Hibs join them there in their first season back in the top flight.
While no Hibs or Kilmarnock player has won the Premiership award previously, Brown is in line to win it for a second time, having topped the polling in 2009.
Last season, it went to Forrest's fellow winger, Scott Sinclair, while Tierney took the young player award for a second year running, having followed in the footsteps of Jason Denayer, the defender who had been on loan to Celtic from Manchester City.
The last non-Celtic player to win the young player award was Tierney's rival for the Scotland left-back position, Andrew Robertson, then of Dundee United and now of Liverpool, in 2014.
Colombia Under-20s striker Morelos is the only non-Scot to make the nominations list and has scored 18 goals in all competitions - three behind Boyd - since his summer transfer from HJK Helsinki.
McKenna only broke into Aberdeen's first team in September and has gone on to win two Scotland caps.
Morgan is also in the running to be Championship player of the year, with nominations for the second tier, League One and League Two having been announced last week.
The winners will be announced at the PFA Scotland awards dinner in Glasgow on 29 April.
Scottish Premiership Player of the Year
Kris Boyd (Kilmarnock): Striker. Aged 34. Former clubs: Rangers, Middlesbrough, Nottingham Forest, Eskisehirspor and Portland Timbers, 18 Scotland caps. 21 goals in 38 appearances.
Scott Brown (Celtic): Midfielder. Aged 32. In 11th season with Celtic since joining from Hibernian. Retired from Scotland duty with 55 caps. Captained Celtic to League Cup final win over Motherwell, one win away from seventh consecutive title and face Well in Scottish Cup final. Premier League Player of the Year 2008-09.
James Forrest (Celtic): Winger. Aged 26, product of Celtic youth system, 20 Scotland caps. 16 goals in 58 appearances.
John McGinn (Hibernian): Midfielder. Aged 23. Joined Hibs from St Mirren in 2015, seven Scotland caps. 6 goals in 43 appearances.
SPFL Young Player of the Year
Scott McKenna (Aberdeen): Centre-half. Aged 21. First season in Aberdeen first team after loan spells with Ayr United and Alloa Athletic. Won two Scotland caps.
Alfredo Morelos (Rangers): Striker. Aged 21. Joined Rangers from HJK Helsinki in June, Colombia Under-20 international. 18 goals in 40 appearances.
Lewis Morgan (St Mirren, on loan from Celtic): Winger. Aged 21. Started with Rangers youths before coming through St Mirren's youth system, sold to Celtic in January and loaned back. 18 goals in 41 appearances helped the Buddies win the Championship title and promotion.
Kieran Tierney (Celtic): Left-back. Aged 20. Product of Celtic youth system, nine Scotland caps. SPFL Young Player of the Year 2015-16 and 2016-17.